feat: enhance profile editing with avatar support and UI adjustments

- Added AvatarPath to ProfileEditResult for user profile updates.
- Updated ProfileEditDialog to include avatar selection with a browse button.
- Increased dialog height to accommodate new avatar input fields.
- Implemented avatar file path handling in the profile edit dialog.

feat: introduce moderation features and user roles

- Added ServerRole enum to define user roles (Member, Mod, Admin, Owner).
- Extended User model to include role, mute, and ban status.
- Created ModerationController for user role assignment, kicking, banning, and muting.
- Implemented methods in IChatBroadcaster and SignalRBroadcaster for user moderation actions.
- Updated database schema with new columns for user roles and moderation states.

fix: ensure muted users cannot send messages

- Added mute status checks in ChatService to prevent message sending for muted users.
- Updated user presence and status handling to reflect role changes and moderation actions.

chore: update constants for ASCII art rendering

- Introduced AsciiArtHeightHalfBlock constant for improved ASCII art rendering.

src/EchoHub.Client/AppOrchestrator.cs

@@ -76,6 +76,7 @@ public sealed class AppOrchestrator : IDisposable
         _mainWindow.OnThemeSelected += HandleThemeSelected;
         _mainWindow.OnSavedServersRequested += HandleSavedServersRequested;
         _mainWindow.OnCreateChannelRequested += HandleCreateChannelRequested;
+        _mainWindow.OnDeleteChannelRequested += HandleDeleteChannelRequested;
     }
 
     // ── Command Handler Wiring ─────────────────────────────────────────────
@@ -292,6 +293,56 @@ public sealed class AppOrchestrator : IDisposable
             }
         };
 
+        _commandHandler.OnKickUser += async (username, reason) =>
+        {
+            if (!IsAuthenticated) return;
+            await _apiClient!.KickUserAsync(username, reason);
+        };
+
+        _commandHandler.OnBanUser += async (username, reason) =>
+        {
+            if (!IsAuthenticated) return;
+            await _apiClient!.BanUserAsync(username, reason);
+        };
+
+        _commandHandler.OnUnbanUser += async (username) =>
+        {
+            if (!IsAuthenticated) return;
+            await _apiClient!.UnbanUserAsync(username);
+        };
+
+        _commandHandler.OnMuteUser += async (username, duration) =>
+        {
+            if (!IsAuthenticated) return;
+            await _apiClient!.MuteUserAsync(username, duration);
+        };
+
+        _commandHandler.OnUnmuteUser += async (username) =>
+        {
+            if (!IsAuthenticated) return;
+            await _apiClient!.UnmuteUserAsync(username);
+        };
+
+        _commandHandler.OnAssignRole += async (username, roleStr) =>
+        {
+            if (!IsAuthenticated) return;
+            var role = roleStr switch
+            {
+                "admin" => ServerRole.Admin,
+                "mod" => ServerRole.Mod,
+                _ => ServerRole.Member,
+            };
+            await _apiClient!.AssignRoleAsync(username, role);
+        };
+
+        _commandHandler.OnNukeChannel += async () =>
+        {
+            if (!IsAuthenticated) return;
+            var channel = _mainWindow.CurrentChannel;
+            if (string.IsNullOrEmpty(channel)) return;
+            await _apiClient!.NukeChannelAsync(channel);
+        };
+
         _commandHandler.OnQuit += () =>
         {
             InvokeUI(() => _app.RequestStop());
@@ -361,6 +412,7 @@ public sealed class AppOrchestrator : IDisposable
                 // History might not be available
             }
 
+            FetchAndUpdateOnlineUsers();
             SaveServerToConfig(result);
         }, "Connection failed", "Connect");
     }
@@ -440,6 +492,8 @@ public sealed class AppOrchestrator : IDisposable
             {
                 // History might not be available
             }
+
+            FetchAndUpdateOnlineUsers();
         }, "Failed to join channel");
     }
 
@@ -526,6 +580,45 @@ public sealed class AppOrchestrator : IDisposable
                 });
             }
 
+            // Upload avatar if specified
+            if (editResult.AvatarPath is not null)
+            {
+                try
+                {
+                    Stream stream;
+                    string fileName;
+
+                    if (Uri.TryCreate(editResult.AvatarPath, UriKind.Absolute, out var uri)
+                        && (uri.Scheme == "http" || uri.Scheme == "https"))
+                    {
+                        using var http = new HttpClient();
+                        var bytes = await http.GetByteArrayAsync(uri);
+                        stream = new MemoryStream(bytes);
+                        fileName = Path.GetFileName(uri.LocalPath);
+                        if (string.IsNullOrWhiteSpace(fileName) || !fileName.Contains('.'))
+                            fileName = "avatar.png";
+                    }
+                    else
+                    {
+                        stream = File.OpenRead(editResult.AvatarPath);
+                        fileName = Path.GetFileName(editResult.AvatarPath);
+                    }
+
+                    await using (stream)
+                    {
+                        await _apiClient!.UploadAvatarAsync(stream, fileName);
+                        var channel = _mainWindow.CurrentChannel;
+                        if (!string.IsNullOrEmpty(channel))
+                            InvokeUI(() => _mainWindow.AddSystemMessage(channel, "Avatar updated."));
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Log.Error(ex, "Avatar upload failed for {Target}", editResult.AvatarPath);
+                    InvokeUI(() => _mainWindow.ShowError($"Avatar upload failed: {ex.Message}"));
+                }
+            }
+
             _config.DefaultPreset = new AccountPreset
             {
                 DisplayName = editResult.DisplayName,
@@ -617,6 +710,47 @@ public sealed class AppOrchestrator : IDisposable
         }, "Failed to create channel");
     }
 
+    private void HandleDeleteChannelRequested()
+    {
+        if (!IsAuthenticated || !IsConnected)
+        {
+            _mainWindow.ShowError("Not connected to a server.");
+            return;
+        }
+
+        var channel = _mainWindow.CurrentChannel;
+        if (string.IsNullOrEmpty(channel))
+        {
+            _mainWindow.ShowError("No channel selected.");
+            return;
+        }
+
+        if (channel == HubConstants.DefaultChannel)
+        {
+            _mainWindow.ShowError($"The #{HubConstants.DefaultChannel} channel cannot be deleted.");
+            return;
+        }
+
+        var confirm = MessageBox.Query(_app, "Delete Channel",
+            $"Are you sure you want to delete #{channel}?\nThis will remove all messages permanently.", "Delete", "Cancel");
+
+        if (confirm != 0) return;
+
+        RunAsync(async () =>
+        {
+            await _apiClient!.DeleteChannelAsync(channel);
+            _joinedChannels.Remove(channel);
+
+            var channels = await _apiClient.GetChannelsAsync();
+            InvokeUI(() =>
+            {
+                _mainWindow.SetChannels(channels);
+                _mainWindow.SwitchToChannel(HubConstants.DefaultChannel);
+                _mainWindow.AddSystemMessage(HubConstants.DefaultChannel, $"Channel #{channel} has been deleted.");
+            });
+        }, "Failed to delete channel");
+    }
+
     // ── Connection Event Wiring ────────────────────────────────────────────
 
     private void WireConnectionEvents(EchoHubConnection connection)
@@ -625,10 +759,18 @@ public sealed class AppOrchestrator : IDisposable
             InvokeUI(() => _mainWindow.AddMessage(message));
 
         connection.OnUserJoined += (channelName, username) =>
+        {
             InvokeUI(() => _mainWindow.AddSystemMessage(channelName, $"{username} joined the channel"));
+            if (channelName == _mainWindow.CurrentChannel)
+                FetchAndUpdateOnlineUsers();
+        };
 
         connection.OnUserLeft += (channelName, username) =>
+        {
             InvokeUI(() => _mainWindow.AddSystemMessage(channelName, $"{username} left the channel"));
+            if (channelName == _mainWindow.CurrentChannel)
+                FetchAndUpdateOnlineUsers();
+        };
 
         connection.OnUserStatusChanged += presence =>
         {
@@ -642,6 +784,49 @@ public sealed class AppOrchestrator : IDisposable
                 foreach (var channelName in _mainWindow.GetChannelNames())
                     _mainWindow.AddStatusMessage(channelName, displayName, statusText);
             });
+            FetchAndUpdateOnlineUsers();
+        };
+
+        connection.OnUserKicked += (channelName, username, reason) =>
+        {
+            var reasonText = reason is not null ? $" ({reason})" : "";
+            InvokeUI(() =>
+            {
+                _mainWindow.AddSystemMessage(channelName, $"{username} was kicked{reasonText}");
+                if (username.Equals(_currentUsername, StringComparison.OrdinalIgnoreCase))
+                {
+                    _mainWindow.AddSystemMessage(channelName, "You were kicked from this channel.");
+                }
+            });
+        };
+
+        connection.OnUserBanned += (username, reason) =>
+        {
+            InvokeUI(() =>
+            {
+                if (username.Equals(_currentUsername, StringComparison.OrdinalIgnoreCase))
+                {
+                    _mainWindow.ShowError("You have been banned from this server.");
+                    HandleDisconnect();
+                }
+            });
+        };
+
+        connection.OnMessageDeleted += (channelName, messageId) =>
+        {
+            InvokeUI(() =>
+            {
+                _mainWindow.RemoveMessage(channelName, messageId);
+            });
+        };
+
+        connection.OnChannelNuked += channelName =>
+        {
+            InvokeUI(() =>
+            {
+                _mainWindow.ClearChannelMessages(channelName);
+                _mainWindow.AddSystemMessage(channelName, "Channel history has been cleared by a moderator.");
+            });
         };
 
         connection.OnError += errorMessage =>
@@ -673,6 +858,25 @@ public sealed class AppOrchestrator : IDisposable
 
     // ── Private Helpers ────────────────────────────────────────────────────
 
+    private void FetchAndUpdateOnlineUsers()
+    {
+        var channel = _mainWindow.CurrentChannel;
+        if (string.IsNullOrEmpty(channel) || !IsConnected) return;
+
+        Task.Run(async () =>
+        {
+            try
+            {
+                var users = await _connection!.GetOnlineUsersAsync(channel);
+                InvokeUI(() => _mainWindow.UpdateOnlineUsers(users));
+            }
+            catch (Exception ex)
+            {
+                Log.Debug(ex, "Failed to fetch online users for {Channel}", channel);
+            }
+        });
+    }
+
     private void SaveServerToConfig(ConnectDialogResult result)
     {
         var savedServer = new SavedServer

src/EchoHub.Client/Commands/CommandHandler.cs

@@ -18,6 +18,13 @@ public class CommandHandler
     public event Func<string, Task>? OnSetTopic;
     public event Func<Task>? OnListUsers;
     public event Func<string, Task>? OnSetAvatar;
+    public event Func<string, string?, Task>? OnKickUser;
+    public event Func<string, string?, Task>? OnBanUser;
+    public event Func<string, Task>? OnUnbanUser;
+    public event Func<string, int?, Task>? OnMuteUser;
+    public event Func<string, Task>? OnUnmuteUser;
+    public event Func<string, string, Task>? OnAssignRole;
+    public event Func<Task>? OnNukeChannel;
     public event Func<Task>? OnQuit;
     public event Func<Task>? OnHelp;
 
@@ -46,6 +53,13 @@ public class CommandHandler
             "leave" => await HandleLeave(),
             "topic" => await HandleTopic(args),
             "users" => await HandleUsers(),
+            "kick" => await HandleKick(args),
+            "ban" => await HandleBan(args),
+            "unban" => await HandleUnban(args),
+            "mute" => await HandleMute(args),
+            "unmute" => await HandleUnmute(args),
+            "role" => await HandleRole(args),
+            "nuke" => await HandleNuke(),
             "quit" or "exit" => await HandleQuit(),
             "help" or "?" => await HandleHelp(),
             _ => new CommandResult(true, $"Unknown command: /{command}. Type /help for available commands.", IsError: true),
@@ -212,6 +226,95 @@ public class CommandHandler
         return new CommandResult(true);
     }
 
+    private async Task<CommandResult> HandleKick(string args)
+    {
+        if (string.IsNullOrWhiteSpace(args))
+            return new CommandResult(true, "Usage: /kick <username> [reason]", IsError: true);
+
+        var parts = args.Split(' ', 2, StringSplitOptions.TrimEntries);
+        var username = parts[0];
+        var reason = parts.Length > 1 ? parts[1] : null;
+
+        if (OnKickUser is not null)
+            await OnKickUser(username, reason);
+        return new CommandResult(true, $"Kicking {username}...");
+    }
+
+    private async Task<CommandResult> HandleBan(string args)
+    {
+        if (string.IsNullOrWhiteSpace(args))
+            return new CommandResult(true, "Usage: /ban <username> [reason]", IsError: true);
+
+        var parts = args.Split(' ', 2, StringSplitOptions.TrimEntries);
+        var username = parts[0];
+        var reason = parts.Length > 1 ? parts[1] : null;
+
+        if (OnBanUser is not null)
+            await OnBanUser(username, reason);
+        return new CommandResult(true, $"Banning {username}...");
+    }
+
+    private async Task<CommandResult> HandleUnban(string args)
+    {
+        if (string.IsNullOrWhiteSpace(args))
+            return new CommandResult(true, "Usage: /unban <username>", IsError: true);
+
+        if (OnUnbanUser is not null)
+            await OnUnbanUser(args.Trim());
+        return new CommandResult(true, $"Unbanning {args.Trim()}...");
+    }
+
+    private async Task<CommandResult> HandleMute(string args)
+    {
+        if (string.IsNullOrWhiteSpace(args))
+            return new CommandResult(true, "Usage: /mute <username> [duration_minutes]", IsError: true);
+
+        var parts = args.Split(' ', 2, StringSplitOptions.TrimEntries);
+        var username = parts[0];
+        int? duration = parts.Length > 1 && int.TryParse(parts[1], out var d) ? d : null;
+
+        if (OnMuteUser is not null)
+            await OnMuteUser(username, duration);
+        return new CommandResult(true, $"Muting {username}...");
+    }
+
+    private async Task<CommandResult> HandleUnmute(string args)
+    {
+        if (string.IsNullOrWhiteSpace(args))
+            return new CommandResult(true, "Usage: /unmute <username>", IsError: true);
+
+        if (OnUnmuteUser is not null)
+            await OnUnmuteUser(args.Trim());
+        return new CommandResult(true, $"Unmuting {args.Trim()}...");
+    }
+
+    private async Task<CommandResult> HandleRole(string args)
+    {
+        if (string.IsNullOrWhiteSpace(args))
+            return new CommandResult(true, "Usage: /role <username> <admin|mod|member>", IsError: true);
+
+        var parts = args.Split(' ', 2, StringSplitOptions.TrimEntries);
+        if (parts.Length < 2)
+            return new CommandResult(true, "Usage: /role <username> <admin|mod|member>", IsError: true);
+
+        var username = parts[0];
+        var role = parts[1].ToLowerInvariant();
+
+        if (role is not ("admin" or "mod" or "member"))
+            return new CommandResult(true, "Invalid role. Use: admin, mod, or member", IsError: true);
+
+        if (OnAssignRole is not null)
+            await OnAssignRole(username, role);
+        return new CommandResult(true, $"Setting {username} to {role}...");
+    }
+
+    private async Task<CommandResult> HandleNuke()
+    {
+        if (OnNukeChannel is not null)
+            await OnNukeChannel();
+        return new CommandResult(true, "Nuking channel history...");
+    }
+
     private async Task<CommandResult> HandleHelp()
     {
         if (OnHelp is not null)
@@ -225,12 +328,20 @@ public class CommandHandler
               /theme <name>                        - Switch theme
               /send <filepath or URL>               - Send a file or image
               /avatar <URL or filepath>             - Set your avatar
-              /profile [username]                   - View a profile (yours if no name given)
+              /profile [username]                   - View a profile
               /servers                             - Open saved servers
               /join <channel>                      - Join a channel
               /leave                               - Leave current channel
               /topic <text>                        - Set channel topic
               /users                               - List online users
+            Moderation:
+              /kick <user> [reason]                - Kick a user (Mod+)
+              /ban <user> [reason]                 - Ban a user (Admin+)
+              /unban <user>                        - Unban a user (Admin+)
+              /mute <user> [minutes]               - Mute a user (Mod+)
+              /unmute <user>                       - Unmute a user (Mod+)
+              /role <user> <admin|mod|member>      - Assign role (Admin+)
+              /nuke                                - Clear channel history (Mod+)
               /quit                                - Exit the app
             """);
     }

src/EchoHub.Client/Services/ApiClient.cs

@@ -3,6 +3,7 @@ using System.Net.Http.Headers;
 using System.Net.Http.Json;
 using System.Text.Json;
 using EchoHub.Core.DTOs;
+using EchoHub.Core.Models;
 
 namespace EchoHub.Client.Services;
 
@@ -211,6 +212,72 @@ public sealed class ApiClient : IDisposable
         await EnsureSuccessAsync(response);
     }
 
+    // ── Moderation ────────────────────────────────────────────────────────
+
+    public async Task AssignRoleAsync(string username, ServerRole role)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.PostAsJsonAsync("/api/moderation/role", new AssignRoleRequest(username, role)));
+        await EnsureSuccessAsync(response);
+    }
+
+    public async Task KickUserAsync(string username, string? reason = null)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.PostAsJsonAsync($"/api/moderation/kick/{Uri.EscapeDataString(username)}", new KickRequest(reason)));
+        await EnsureSuccessAsync(response);
+    }
+
+    public async Task BanUserAsync(string username, string? reason = null)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.PostAsJsonAsync($"/api/moderation/ban/{Uri.EscapeDataString(username)}", new BanRequest(reason)));
+        await EnsureSuccessAsync(response);
+    }
+
+    public async Task UnbanUserAsync(string username)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.PostAsJsonAsync($"/api/moderation/unban/{Uri.EscapeDataString(username)}", new {}));
+        await EnsureSuccessAsync(response);
+    }
+
+    public async Task MuteUserAsync(string username, int? durationMinutes = null, string? reason = null)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.PostAsJsonAsync($"/api/moderation/mute/{Uri.EscapeDataString(username)}", new MuteRequest(reason, durationMinutes)));
+        await EnsureSuccessAsync(response);
+    }
+
+    public async Task UnmuteUserAsync(string username)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.PostAsJsonAsync($"/api/moderation/unmute/{Uri.EscapeDataString(username)}", new {}));
+        await EnsureSuccessAsync(response);
+    }
+
+    public async Task DeleteMessageAsync(Guid messageId)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.DeleteAsync($"/api/moderation/messages/{messageId}"));
+        await EnsureSuccessAsync(response);
+    }
+
+    public async Task NukeChannelAsync(string channelName)
+    {
+        EnsureAuthenticated();
+        var response = await AuthenticatedRequestAsync(() =>
+            _http.DeleteAsync($"/api/moderation/channels/{Uri.EscapeDataString(channelName)}/nuke"));
+        await EnsureSuccessAsync(response);
+    }
+
     private void SetTokens(LoginResponse result)
     {
         _accessToken = result.Token;

src/EchoHub.Client/Services/EchoHubConnection.cs

@@ -14,6 +14,10 @@ public sealed class EchoHubConnection : IAsyncDisposable
     public event Action<string, string>? OnUserLeft;
     public event Action<ChannelDto>? OnChannelUpdated;
     public event Action<UserPresenceDto>? OnUserStatusChanged;
+    public event Action<string, string, string?>? OnUserKicked;
+    public event Action<string, string?>? OnUserBanned;
+    public event Action<string, Guid>? OnMessageDeleted;
+    public event Action<string>? OnChannelNuked;
     public event Action<string>? OnError;
     public event Action<string>? OnConnectionStateChanged;
     public event Action? OnReconnected;
@@ -81,6 +85,26 @@ public sealed class EchoHubConnection : IAsyncDisposable
             OnUserStatusChanged?.Invoke(presence);
         });
 
+        _connection.On<string, string, string?>(nameof(Core.Contracts.IEchoHubClient.UserKicked), (channelName, username, reason) =>
+        {
+            OnUserKicked?.Invoke(channelName, username, reason);
+        });
+
+        _connection.On<string, string?>(nameof(Core.Contracts.IEchoHubClient.UserBanned), (username, reason) =>
+        {
+            OnUserBanned?.Invoke(username, reason);
+        });
+
+        _connection.On<string, Guid>(nameof(Core.Contracts.IEchoHubClient.MessageDeleted), (channelName, messageId) =>
+        {
+            OnMessageDeleted?.Invoke(channelName, messageId);
+        });
+
+        _connection.On<string>(nameof(Core.Contracts.IEchoHubClient.ChannelNuked), channelName =>
+        {
+            OnChannelNuked?.Invoke(channelName);
+        });
+
         _connection.On<string>(nameof(Core.Contracts.IEchoHubClient.Error), message =>
         {
             OnError?.Invoke(message);

src/EchoHub.Client/UI/ChatRenderer.cs

@@ -20,6 +20,8 @@ public partial class ChatLine
 {
     public List<ChatSegment> Segments { get; }
     public int TextLength { get; }
+    public Guid? MessageId { get; set; }
+    public bool IsMention { get; set; }
 
     public ChatLine(string plainText)
     {
@@ -89,14 +91,25 @@ public partial class ChatLine
 
     /// <summary>
     /// Parse a string containing ANSI 24-bit color escape codes into colored segments.
-    /// Format: \x1b[38;2;R;G;Bm (foreground color), \x1b[0m (reset)
+    /// Supports foreground (\x1b[38;2;R;G;Bm), background (\x1b[48;2;R;G;Bm), and reset (\x1b[0m).
     /// </summary>
     public static ChatLine FromAnsi(string ansiText, Attribute? defaultAttr = null)
     {
         var segments = new List<ChatSegment>();
         var regex = AnsiColorRegex();
         int lastIndex = 0;
-        Attribute? currentColor = defaultAttr;
+        Color? currentFg = null;
+        Color? currentBg = null;
+        var defaultFg = defaultAttr?.Foreground;
+        var defaultBg = defaultAttr?.Background ?? Color.Black;
+
+        Attribute? BuildAttr()
+        {
+            if (currentFg is null && currentBg is null) return defaultAttr;
+            var fg = currentFg ?? defaultFg ?? Color.White;
+            var bg = currentBg ?? defaultBg;
+            return new Attribute(fg, bg);
+        }
 
         foreach (Match match in regex.Matches(ansiText))
         {
@@ -105,22 +118,26 @@ public partial class ChatLine
             {
                 var text = ansiText[lastIndex..match.Index];
                 if (text.Length > 0)
-                    segments.Add(new ChatSegment(text, currentColor));
+                    segments.Add(new ChatSegment(text, BuildAttr()));
             }
 
             // Parse the escape sequence
             if (match.Groups[1].Value == "0")
             {
                 // Reset
-                currentColor = defaultAttr;
+                currentFg = null;
+                currentBg = null;
             }
             else if (match.Groups[2].Success)
             {
-                // 38;2;R;G;B — 24-bit foreground color
                 var r = int.Parse(match.Groups[3].Value);
                 var g = int.Parse(match.Groups[4].Value);
                 var b = int.Parse(match.Groups[5].Value);
-                currentColor = new Attribute(new Color(r, g, b), Color.Black);
+
+                if (match.Groups[2].Value == "38;2")
+                    currentFg = new Color(r, g, b);
+                else // 48;2
+                    currentBg = new Color(r, g, b);
             }
 
             lastIndex = match.Index + match.Length;
@@ -131,14 +148,14 @@ public partial class ChatLine
         {
             var text = ansiText[lastIndex..];
             if (text.Length > 0)
-                segments.Add(new ChatSegment(text, currentColor));
+                segments.Add(new ChatSegment(text, BuildAttr()));
         }
 
         return segments.Count > 0 ? new ChatLine(segments) : new ChatLine("");
     }
 
-    // Matches: \x1b[0m (reset) or \x1b[38;2;R;G;Bm (24-bit foreground)
-    [GeneratedRegex(@"\x1b\[(?:(0)|(?:(38;2);(\d{1,3});(\d{1,3});(\d{1,3})))m")]
+    // Matches: \x1b[0m (reset), \x1b[38;2;R;G;Bm (fg), or \x1b[48;2;R;G;Bm (bg)
+    [GeneratedRegex(@"\x1b\[(?:(0)|(?:(38;2|48;2);(\d{1,3});(\d{1,3});(\d{1,3})))m")]
     private static partial Regex AnsiColorRegex();
 }
 
@@ -198,6 +215,7 @@ public class ChatListSource : IListDataSource
 
         var chatLine = _lines[item];
         var normalAttr = listView.GetAttributeForRole(selected ? VisualRole.Focus : VisualRole.Normal);
+        var mentionBg = chatLine.IsMention ? ChatColors.MentionHighlightAttr.Background : (Color?)null;
 
         int charPos = 0;
         int drawnChars = 0;
@@ -205,6 +223,9 @@ public class ChatListSource : IListDataSource
         foreach (var segment in chatLine.Segments)
         {
             var attr = segment.Color ?? normalAttr;
+            // Override background for mention-highlighted lines
+            if (mentionBg.HasValue)
+                attr = new Attribute(attr.Foreground, mentionBg.Value);
             listView.SetAttribute(attr);
 
             foreach (var ch in segment.Text)
@@ -218,8 +239,9 @@ public class ChatListSource : IListDataSource
             }
         }
 
-        // Fill remaining width with spaces using default colors
-        listView.SetAttribute(normalAttr);
+        // Fill remaining width with spaces
+        var fillAttr = mentionBg.HasValue ? new Attribute(normalAttr.Foreground, mentionBg.Value) : normalAttr;
+        listView.SetAttribute(fillAttr);
         while (drawnChars < width)
         {
             listView.AddRune(new Rune(' '));
@@ -242,6 +264,110 @@ public class ChatListSource : IListDataSource
     public void Dispose() { }
 }
 
+/// <summary>
+/// Custom list data source for colored channel list rendering.
+/// Active channel gets a > indicator, unread channels are bright with a count badge.
+/// </summary>
+public class ChannelListSource : IListDataSource
+{
+    private readonly List<string> _channelNames = [];
+    private readonly Dictionary<string, int> _unreadCounts = [];
+    private string _activeChannel = string.Empty;
+
+    public event NotifyCollectionChangedEventHandler? CollectionChanged;
+    public int Count => _channelNames.Count;
+    public int MaxItemLength { get; private set; }
+    public bool SuspendCollectionChangedEvent { get; set; }
+
+    private static readonly Attribute ActiveAttr = new(Color.White, Color.Black);
+    private static readonly Attribute UnreadAttr = new(Color.BrightCyan, Color.Black);
+    private static readonly Attribute NormalAttr = new(Color.DarkGray, Color.Black);
+    private static readonly Attribute BadgeAttr = new(Color.BrightYellow, Color.Black);
+
+    public void Update(List<string> channels, Dictionary<string, int> unread, string activeChannel)
+    {
+        _channelNames.Clear();
+        _channelNames.AddRange(channels);
+        _unreadCounts.Clear();
+        foreach (var kv in unread)
+            _unreadCounts[kv.Key] = kv.Value;
+        _activeChannel = activeChannel;
+        MaxItemLength = channels.Count > 0 ? channels.Max(c => c.Length + 6) : 0;
+        if (!SuspendCollectionChangedEvent)
+            CollectionChanged?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
+    }
+
+    public bool IsMarked(int item) => false;
+    public void SetMark(int item, bool value) { }
+    public IList ToList() => _channelNames.Select(n => $"#{n}").ToList();
+
+    public void Render(ListView listView, bool selected, int item, int col, int row, int width, int viewportX = 0)
+    {
+        listView.Move(Math.Max(col - viewportX, 0), row);
+
+        var name = _channelNames[item];
+        var isActive = name == _activeChannel;
+        _unreadCounts.TryGetValue(name, out var unread);
+        var hasUnread = unread > 0;
+
+        var focusAttr = listView.GetAttributeForRole(VisualRole.Focus);
+        var prefix = isActive ? "> " : "  ";
+        var channelText = $"#{name}";
+        var badge = hasUnread ? $" ({unread})" : "";
+
+        int drawnChars = 0;
+
+        // Use focus attr if this row is selected
+        if (selected)
+        {
+            listView.SetAttribute(focusAttr);
+            foreach (var ch in (prefix + channelText + badge))
+            {
+                if (drawnChars < width) { listView.AddRune(new Rune(ch)); drawnChars++; }
+            }
+        }
+        else
+        {
+            // Prefix
+            var prefixAttr = isActive ? ActiveAttr : NormalAttr;
+            listView.SetAttribute(prefixAttr);
+            foreach (var ch in prefix)
+            {
+                if (drawnChars < width) { listView.AddRune(new Rune(ch)); drawnChars++; }
+            }
+
+            // Channel name
+            var nameAttr = isActive ? ActiveAttr : hasUnread ? UnreadAttr : NormalAttr;
+            listView.SetAttribute(nameAttr);
+            foreach (var ch in channelText)
+            {
+                if (drawnChars < width) { listView.AddRune(new Rune(ch)); drawnChars++; }
+            }
+
+            // Unread badge
+            if (hasUnread)
+            {
+                listView.SetAttribute(BadgeAttr);
+                foreach (var ch in badge)
+                {
+                    if (drawnChars < width) { listView.AddRune(new Rune(ch)); drawnChars++; }
+                }
+            }
+        }
+
+        // Fill rest
+        var fillAttr = selected ? focusAttr : listView.GetAttributeForRole(VisualRole.Normal);
+        listView.SetAttribute(fillAttr);
+        while (drawnChars < width)
+        {
+            listView.AddRune(new Rune(' '));
+            drawnChars++;
+        }
+    }
+
+    public void Dispose() { }
+}
+
 /// <summary>
 /// Shared color attributes for chat rendering (timestamps, system messages).
 /// </summary>
@@ -249,6 +375,7 @@ public static class ChatColors
 {
     public static readonly Attribute TimestampAttr = new(Color.DarkGray, Color.Black);
     public static readonly Attribute SystemAttr = new(new Color(0, 180, 180), Color.Black);
+    public static readonly Attribute MentionHighlightAttr = new(Color.White, new Color(80, 40, 0));
 }
 
 /// <summary>

src/EchoHub.Client/UI/MainWindow.cs

@@ -1,4 +1,5 @@
 using System.Collections.ObjectModel;
+using System.Text.RegularExpressions;
 using EchoHub.Client.Themes;
 using EchoHub.Core.DTOs;
 using EchoHub.Core.Models;
@@ -21,10 +22,21 @@ public sealed class MainWindow : Runnable
     private readonly ListView _messageList;
     private readonly TextView _inputField;
     private readonly FrameView _chatFrame;
+    private readonly FrameView _inputFrame;
     private readonly Label _statusLabel;
     private readonly Label _topicLabel;
     private MenuBar _menuBar;
 
+    // Online users panel
+    private readonly FrameView _usersFrame;
+    private readonly ListView _usersList;
+    private bool _usersPanelVisible = true;
+    private const int UsersPanelWidth = 22;
+    private static readonly Key F2Key = Key.F2;
+
+    private static readonly string AppVersion =
+        typeof(MainWindow).Assembly.GetName().Version?.ToString(3) ?? "?";
+
     // Cached Key constants — compare via .KeyCode to avoid Key.Equals (which also checks Handled)
     private static readonly Key EnterKey = Key.Enter;
     private static readonly Key NewlineKey = Key.N.WithCtrl;
@@ -36,13 +48,15 @@ public sealed class MainWindow : Runnable
     [
         "/status", "/nick", "/color", "/theme", "/send",
         "/avatar", "/profile", "/servers", "/join", "/leave",
-        "/topic", "/users", "/quit", "/help"
+        "/topic", "/users", "/kick", "/ban", "/unban",
+        "/mute", "/unmute", "/role", "/nuke", "/quit", "/help"
     ];
 
     private readonly List<string> _channelNames = [];
     private readonly Dictionary<string, List<ChatLine>> _channelMessages = [];
     private readonly Dictionary<string, int> _channelUnread = [];
     private readonly Dictionary<string, string?> _channelTopics = [];
+    private readonly ChannelListSource _channelListSource;
     private string _currentChannel = string.Empty;
     private string _currentUser = string.Empty;
     private int _lastChatWidth;
@@ -92,6 +106,11 @@ public sealed class MainWindow : Runnable
     /// </summary>
     public event Action? OnCreateChannelRequested;
 
+    /// <summary>
+    /// Fired when the user requests to delete the current channel.
+    /// </summary>
+    public event Action? OnDeleteChannelRequested;
+
     public MainWindow(IApplication app)
     {
         _app = app;
@@ -107,7 +126,7 @@ public sealed class MainWindow : Runnable
             Title = "Channels",
             X = 0,
             Y = 1, // below menu bar
-            Width = 25,
+            Width = 22,
             Height = Dim.Fill(1) // leave room for status bar
         };
 
@@ -118,7 +137,8 @@ public sealed class MainWindow : Runnable
             Width = Dim.Fill(),
             Height = Dim.Fill()
         };
-        _channelList.SetSource(new ObservableCollection<string>(_channelNames));
+        _channelListSource = new ChannelListSource();
+        _channelList.Source = _channelListSource;
         _channelList.ValueChanged += OnChannelListSelectionChanged;
         channelsFrame.Add(_channelList);
         Add(channelsFrame);
@@ -127,9 +147,9 @@ public sealed class MainWindow : Runnable
         _topicLabel = new Label
         {
             Text = "",
-            X = 25,
+            X = 22,
             Y = 1,
-            Width = Dim.Fill(),
+            Width = Dim.Fill(UsersPanelWidth),
             Height = 1,
             Visible = false
         };
@@ -139,9 +159,9 @@ public sealed class MainWindow : Runnable
         _chatFrame = new FrameView
         {
             Title = "Chat",
-            X = 25,
+            X = 22,
             Y = 1, // below menu bar (shifts to 2 when topic is visible)
-            Width = Dim.Fill(),
+            Width = Dim.Fill(UsersPanelWidth),
             Height = Dim.Fill(6) // leave room for input area and status bar
         };
 
@@ -157,12 +177,12 @@ public sealed class MainWindow : Runnable
         Add(_chatFrame);
 
         // Bottom input area
-        var inputFrame = new FrameView
+        _inputFrame = new FrameView
         {
-            Title = "Message (Enter=send, Ctrl+N=newline, Tab=autocomplete)",
-            X = 25,
+            Title = "Message \u2502 Enter=send \u2502 Ctrl+N=newline \u2502 Tab=complete",
+            X = 22,
             Y = Pos.Bottom(_chatFrame),
-            Width = Dim.Fill(),
+            Width = Dim.Fill(UsersPanelWidth),
             Height = 5
         };
 
@@ -175,8 +195,29 @@ public sealed class MainWindow : Runnable
             WordWrap = true
         };
         _inputField.KeyDown += OnInputKeyDown;
-        inputFrame.Add(_inputField);
-        Add(inputFrame);
+        _inputFrame.Add(_inputField);
+        Add(_inputFrame);
+
+        // Right panel - online users
+        _usersFrame = new FrameView
+        {
+            Title = "Users",
+            X = Pos.AnchorEnd(UsersPanelWidth),
+            Y = 1,
+            Width = UsersPanelWidth,
+            Height = Dim.Fill(1)
+        };
+
+        _usersList = new ListView
+        {
+            X = 0,
+            Y = 0,
+            Width = Dim.Fill(),
+            Height = Dim.Fill()
+        };
+        _usersList.SetSource(new ObservableCollection<string>());
+        _usersFrame.Add(_usersList);
+        Add(_usersFrame);
 
         // Status bar at the very bottom
         _statusLabel = new Label
@@ -198,7 +239,7 @@ public sealed class MainWindow : Runnable
         _messageList.ViewportChanged += (_, _) => OnChatViewportChanged();
         _chatFrame.ViewportChanged += (_, _) => OnChatViewportChanged();
 
-        // Window-level key handling for Ctrl+C (quit)
+        // Window-level key handling for Ctrl+C (quit), F2 (toggle users panel)
         KeyDown += OnWindowKeyDown;
     }
 
@@ -265,7 +306,11 @@ public sealed class MainWindow : Runnable
                 new MenuItem("_Disconnect", "Disconnect from server", () => OnDisconnectRequested?.Invoke(), Key.Empty),
                 new Line(),
                 new MenuItem("New C_hannel...", "Create a new channel", () => OnCreateChannelRequested?.Invoke(), Key.Empty),
-                new MenuItem("_Saved Servers...", "View saved servers", () => OnSavedServersRequested?.Invoke(), Key.Empty)
+                new MenuItem("_Delete Channel", "Delete the current channel", () => OnDeleteChannelRequested?.Invoke(), Key.Empty),
+                new Line(),
+                new MenuItem("_Saved Servers...", "View saved servers", () => OnSavedServersRequested?.Invoke(), Key.Empty),
+                new Line(),
+                new MenuItem("Toggle _Users Panel", "Toggle online users (F2)", () => ToggleUsersPanel(), Key.Empty)
             }),
             new MenuBarItem("_User", allUserItems)
         ]);
@@ -386,12 +431,16 @@ public sealed class MainWindow : Runnable
 
     private void OnWindowKeyDown(object? sender, Key e)
     {
-        // Ctrl+C quits from anywhere
         if (e.KeyCode == CtrlCKey.KeyCode)
         {
             _app.RequestStop();
             e.Handled = true;
         }
+        else if (e.KeyCode == F2Key.KeyCode)
+        {
+            ToggleUsersPanel();
+            e.Handled = true;
+        }
     }
 
     /// <summary>
@@ -475,6 +524,32 @@ public sealed class MainWindow : Runnable
         }
     }
 
+    /// <summary>
+    /// Remove all lines associated with a specific message ID.
+    /// </summary>
+    public void RemoveMessage(string channelName, Guid messageId)
+    {
+        if (_channelMessages.TryGetValue(channelName, out var messages))
+        {
+            messages.RemoveAll(l => l.MessageId == messageId);
+            if (channelName == _currentChannel)
+                RefreshMessages();
+        }
+    }
+
+    /// <summary>
+    /// Clear all messages from a specific channel.
+    /// </summary>
+    public void ClearChannelMessages(string channelName)
+    {
+        if (_channelMessages.TryGetValue(channelName, out var messages))
+        {
+            messages.Clear();
+            if (channelName == _currentChannel)
+                RefreshMessages();
+        }
+    }
+
     /// <summary>
     /// Set the list of available channels, storing topics, and refresh the channel list view.
     /// </summary>
@@ -515,9 +590,9 @@ public sealed class MainWindow : Runnable
     /// </summary>
     public void UpdateStatusBar(string status)
     {
-        var userPart = string.IsNullOrEmpty(_currentUser) ? "" : $" | User: {_currentUser}";
-        var channelPart = string.IsNullOrEmpty(_currentChannel) ? "" : $" | #{_currentChannel}";
-        _statusLabel.Text = $" {status}{userPart}{channelPart}";
+        var userPart = string.IsNullOrEmpty(_currentUser) ? "" : $" \u2502 User: {_currentUser}";
+        var channelPart = string.IsNullOrEmpty(_currentChannel) ? "" : $" \u2502 #{_currentChannel}";
+        _statusLabel.Text = $" v{AppVersion} \u2502 {status}{userPart}{channelPart}";
     }
 
     /// <summary>
@@ -585,10 +660,13 @@ public sealed class MainWindow : Runnable
         _channelTopics.Clear();
         _currentChannel = string.Empty;
         _currentUser = string.Empty;
-        _channelList.SetSource(new ObservableCollection<string>(_channelNames));
+        _channelListSource.Update([], [], string.Empty);
+        _channelList.Source = _channelListSource;
         _chatFrame.Title = "Chat";
         _topicLabel.Visible = false;
         _chatFrame.Y = 1;
+        _usersList.SetSource(new ObservableCollection<string>());
+        _usersFrame.Title = "Users";
         RefreshMessages();
     }
 
@@ -640,13 +718,8 @@ public sealed class MainWindow : Runnable
     /// </summary>
     private void RefreshChannelList()
     {
-        var displayNames = _channelNames.Select(name =>
-        {
-            _channelUnread.TryGetValue(name, out var unread);
-            return unread > 0 ? $"#{name} ({unread})" : $"#{name}";
-        }).ToList();
-
-        _channelList.SetSource(new ObservableCollection<string>(displayNames));
+        _channelListSource.Update(_channelNames, _channelUnread, _currentChannel);
+        _channelList.Source = _channelListSource;
 
         // Restore selection to current channel
         var idx = _channelNames.IndexOf(_currentChannel);
@@ -673,11 +746,63 @@ public sealed class MainWindow : Runnable
         }
     }
 
+    /// <summary>
+    /// Adjusts widths of chat, topic, and input frames based on users panel visibility.
+    /// </summary>
+    private void UpdateLayout()
+    {
+        var rightMargin = _usersPanelVisible ? UsersPanelWidth : 0;
+        _chatFrame.Width = Dim.Fill(rightMargin);
+        _topicLabel.Width = Dim.Fill(rightMargin);
+        _inputFrame.Width = Dim.Fill(rightMargin);
+        _usersFrame.Visible = _usersPanelVisible;
+        SetNeedsDraw();
+    }
+
+    /// <summary>
+    /// Toggle the online users panel visibility (F2).
+    /// </summary>
+    public void ToggleUsersPanel()
+    {
+        _usersPanelVisible = !_usersPanelVisible;
+        UpdateLayout();
+    }
+
+    /// <summary>
+    /// Update the online users list display.
+    /// </summary>
+    public void UpdateOnlineUsers(List<UserPresenceDto> users)
+    {
+        var displayItems = users.Select(u =>
+        {
+            var statusIcon = u.Status switch
+            {
+                UserStatus.Online => "\u25cf", // ●
+                UserStatus.Away => "\u25cb",   // ○
+                UserStatus.DoNotDisturb => "\u25d0", // ◐
+                UserStatus.Invisible => "\u25cc",    // ◌
+                _ => " "
+            };
+            var name = u.DisplayName ?? u.Username;
+            var roleTag = u.Role switch
+            {
+                ServerRole.Owner => "\u2605", // ★
+                ServerRole.Admin => "\u2666", // ♦
+                ServerRole.Mod => "\u2740",   // ❀
+                _ => ""
+            };
+            return $"{statusIcon} {roleTag}{name}";
+        }).ToList();
+
+        _usersList.SetSource(new ObservableCollection<string>(displayItems));
+        _usersFrame.Title = $"Users ({users.Count})";
+    }
+
     /// <summary>
     /// Format a message DTO into one or more display lines based on its MessageType.
     /// Timestamps are dimmed and sender names are colored.
     /// </summary>
-    private static List<ChatLine> FormatMessage(MessageDto message)
+    private List<ChatLine> FormatMessage(MessageDto message)
     {
         var time = message.SentAt.ToLocalTime().ToString("HH:mm");
         var senderName = message.SenderUsername + ":";
@@ -724,6 +849,21 @@ public sealed class MainWindow : Runnable
                 break;
         }
 
+        // Tag all lines with the message ID for deletion support
+        foreach (var line in lines)
+            line.MessageId = message.Id;
+
+        // Check for @mention of current user
+        if (!string.IsNullOrEmpty(_currentUser) && message.Type == MessageType.Text)
+        {
+            var pattern = $@"@{Regex.Escape(_currentUser)}\b";
+            if (Regex.IsMatch(message.Content, pattern, RegexOptions.IgnoreCase))
+            {
+                foreach (var line in lines)
+                    line.IsMention = true;
+            }
+        }
+
         return lines;
     }
 

src/EchoHub.Client/UI/ProfileEditDialog.cs

@@ -9,7 +9,7 @@ namespace EchoHub.Client.UI;
 /// <summary>
 /// Result returned from the profile edit dialog.
 /// </summary>
-public record ProfileEditResult(string? DisplayName, string? Bio, string? NicknameColor);
+public record ProfileEditResult(string? DisplayName, string? Bio, string? NicknameColor, string? AvatarPath);
 
 /// <summary>
 /// A Terminal.Gui dialog for editing the user's profile (display name, bio, nickname color).
@@ -23,7 +23,7 @@ public sealed class ProfileEditDialog
     {
         ProfileEditResult? result = null;
 
-        var dialog = new Dialog { Title = "Edit Profile", Width = 60, Height = 18 };
+        var dialog = new Dialog { Title = "Edit Profile", Width = 60, Height = 22 };
 
         // Display Name
         var nameLabel = new Label
@@ -102,20 +102,66 @@ public sealed class ProfileEditDialog
             UpdateColorPreview(colorPreview, colorField.Text);
         };
 
+        // Avatar
+        var avatarLabel = new Label
+        {
+            Text = "Avatar:",
+            X = 1,
+            Y = 10
+        };
+        var avatarField = new TextField
+        {
+            Text = "",
+            X = 17,
+            Y = 10,
+            Width = Dim.Fill(12)
+        };
+        var browseButton = new Button
+        {
+            Text = "Browse",
+            X = Pos.AnchorEnd(10),
+            Y = 10
+        };
+        var avatarHintLabel = new Label
+        {
+            Text = "(file path or URL)",
+            X = 17,
+            Y = 11
+        };
+        avatarHintLabel.SetScheme(new Scheme
+        {
+            Normal = new Attribute(Color.DarkGray, Color.Blue)
+        });
+
+        browseButton.Accepting += (s, e) =>
+        {
+            e.Handled = true;
+            var openDialog = new OpenDialog
+            {
+                Title = "Select Avatar Image",
+                OpenMode = OpenMode.File,
+            };
+            app.Run(openDialog);
+            if (openDialog.FilePaths.Count > 0)
+            {
+                avatarField.Text = openDialog.FilePaths[0];
+            }
+        };
+
         // Buttons
         var saveButton = new Button
         {
             Text = "Save",
             IsDefault = true,
             X = Pos.Center() - 10,
-            Y = 10
+            Y = 14
         };
 
         var cancelButton = new Button
         {
             Text = "Cancel",
             X = Pos.Center() + 5,
-            Y = 10
+            Y = 14
         };
 
         saveButton.Accepting += (s, e) =>
@@ -123,8 +169,9 @@ public sealed class ProfileEditDialog
             var displayName = NullIfEmpty(nameField.Text?.Trim());
             var bio = NullIfEmpty(bioField.Text?.Trim());
             var nicknameColor = NullIfEmpty(colorField.Text?.Trim());
+            var avatarPath = NullIfEmpty(avatarField.Text?.Trim());
 
-            result = new ProfileEditResult(displayName, bio, nicknameColor);
+            result = new ProfileEditResult(displayName, bio, nicknameColor, avatarPath);
             e.Handled = true;
             app.RequestStop();
         };
@@ -137,7 +184,9 @@ public sealed class ProfileEditDialog
         };
 
         dialog.Add(nameLabel, nameField, bioLabel, bioField, colorLabel, colorField,
-            colorHintLabel, previewLabel, colorPreview, saveButton, cancelButton);
+            colorHintLabel, previewLabel, colorPreview,
+            avatarLabel, avatarField, browseButton, avatarHintLabel,
+            saveButton, cancelButton);
 
         nameField.SetFocus();
         app.Run(dialog);

src/EchoHub.Core/Constants/HubConstants.cs

@@ -10,4 +10,5 @@ public static class HubConstants
     public const int MaxAvatarSizeBytes = 2 * 1024 * 1024; // 2 MB
     public const int AsciiArtWidth = 80;
     public const int AsciiArtHeight = 40;
+    public const int AsciiArtHeightHalfBlock = 80;
 }

src/EchoHub.Core/Contracts/IChatBroadcaster.cs

@@ -9,5 +9,9 @@ public interface IChatBroadcaster
     Task SendUserLeftAsync(string channelName, string username);
     Task SendChannelUpdatedAsync(ChannelDto channel, string? channelName = null);
     Task SendUserStatusChangedAsync(List<string> channelNames, UserPresenceDto presence);
+    Task SendUserKickedAsync(string channelName, string username, string? reason);
+    Task SendUserBannedAsync(string username, string? reason);
+    Task SendMessageDeletedAsync(string channelName, Guid messageId);
+    Task SendChannelNukedAsync(string channelName);
     Task SendErrorAsync(string connectionId, string message);
 }

src/EchoHub.Core/Contracts/IEchoHubClient.cs

@@ -12,5 +12,9 @@ public interface IEchoHubClient
     Task UserLeft(string channelName, string username);
     Task ChannelUpdated(ChannelDto channel);
     Task UserStatusChanged(UserPresenceDto presence);
+    Task UserKicked(string channelName, string username, string? reason);
+    Task UserBanned(string username, string? reason);
+    Task MessageDeleted(string channelName, Guid messageId);
+    Task ChannelNuked(string channelName);
     Task Error(string message);
 }

src/EchoHub.Core/DTOs/ModerationDtos.cs

@@ -0,0 +1,8 @@
+using EchoHub.Core.Models;
+
+namespace EchoHub.Core.DTOs;
+
+public record AssignRoleRequest(string Username, ServerRole Role);
+public record MuteRequest(string? Reason = null, int? DurationMinutes = null);
+public record BanRequest(string? Reason = null);
+public record KickRequest(string? Reason = null);

src/EchoHub.Core/DTOs/ProfileDtos.cs

@@ -11,6 +11,7 @@ public record UserProfileDto(
     string? AvatarAscii,
     UserStatus Status,
     string? StatusMessage,
+    ServerRole Role,
     DateTimeOffset CreatedAt,
     DateTimeOffset LastSeenAt);
 
@@ -28,6 +29,7 @@ public record UserPresenceDto(
     string? DisplayName,
     string? NicknameColor,
     UserStatus Status,
-    string? StatusMessage);
+    string? StatusMessage,
+    ServerRole Role);
 
 public record AvatarUploadResponse(string AvatarAscii);

src/EchoHub.Core/Models/ServerRole.cs

@@ -0,0 +1,9 @@
+namespace EchoHub.Core.Models;
+
+public enum ServerRole
+{
+    Member = 0,
+    Mod = 1,
+    Admin = 2,
+    Owner = 3
+}

src/EchoHub.Core/Models/User.cs

@@ -11,6 +11,10 @@ public class User
     public string? AvatarAscii { get; set; }
     public UserStatus Status { get; set; } = UserStatus.Online;
     public string? StatusMessage { get; set; }
+    public ServerRole Role { get; set; } = ServerRole.Member;
+    public bool IsMuted { get; set; }
+    public DateTimeOffset? MutedUntil { get; set; }
+    public bool IsBanned { get; set; }
     public DateTimeOffset CreatedAt { get; set; } = DateTimeOffset.UtcNow;
     public DateTimeOffset LastSeenAt { get; set; } = DateTimeOffset.UtcNow;
 }

src/EchoHub.Server.Irc/IrcBroadcaster.cs

@@ -62,6 +62,41 @@ public class IrcBroadcaster : IChatBroadcaster
         return Task.CompletedTask;
     }
 
+    public async Task SendUserKickedAsync(string channelName, string username, string? reason)
+    {
+        var reasonText = reason is not null ? $" :{reason}" : "";
+        foreach (var conn in _gateway.GetConnectionsInChannel(channelName))
+        {
+            await conn.SendAsync($":{_gateway.Options.ServerName} KICK #{channelName} {username}{reasonText}");
+        }
+    }
+
+    public async Task SendUserBannedAsync(string username, string? reason)
+    {
+        var reasonText = reason ?? "You have been banned.";
+        foreach (var conn in _gateway.GetAllConnections())
+        {
+            if (conn.Nickname == username)
+                await conn.SendAsync($":{_gateway.Options.ServerName} NOTICE {username} :You have been banned: {reasonText}");
+        }
+    }
+
+    public async Task SendMessageDeletedAsync(string channelName, Guid messageId)
+    {
+        foreach (var conn in _gateway.GetConnectionsInChannel(channelName))
+        {
+            await conn.SendAsync($":{_gateway.Options.ServerName} NOTICE {conn.Nickname ?? "*"} :Message {messageId} was deleted in #{channelName}");
+        }
+    }
+
+    public async Task SendChannelNukedAsync(string channelName)
+    {
+        foreach (var conn in _gateway.GetConnectionsInChannel(channelName))
+        {
+            await conn.SendAsync($":{_gateway.Options.ServerName} NOTICE {conn.Nickname ?? "*"} :All messages in #{channelName} have been cleared");
+        }
+    }
+
     public async Task SendErrorAsync(string connectionId, string message)
     {
         if (!connectionId.StartsWith("irc-")) return;

src/EchoHub.Server.Irc/IrcGatewayService.cs

@@ -37,6 +37,11 @@ public sealed class IrcGatewayService : BackgroundService
             .Where(c => c.IsAuthenticated && c.JoinedChannels.Contains(channelName));
     }
 
+    public IEnumerable<IrcClientConnection> GetAllConnections()
+    {
+        return _connections.Values.Where(c => c.IsAuthenticated);
+    }
+
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
         await Task.Yield();

src/EchoHub.Server/Auth/JwtTokenService.cs

@@ -37,6 +37,7 @@ public class JwtTokenService
             new(JwtRegisteredClaimNames.Sub, user.Id.ToString()),
             new("username", user.Username),
             new("display_name", user.DisplayName ?? user.Username),
+            new("role", user.Role.ToString()),
             new(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString()),
         ];
 

src/EchoHub.Server/Controllers/AuthController.cs

@@ -42,12 +42,16 @@ public class AuthController : ControllerBase
         if (await _db.Users.AnyAsync(u => u.Username == normalizedUsername))
             return Conflict(new ErrorResponse("Username is already taken."));
 
+        // First registered user on the server becomes the Owner
+        var isFirstUser = !await _db.Users.AnyAsync();
+
         var user = new User
         {
             Id = Guid.NewGuid(),
             Username = normalizedUsername,
             PasswordHash = BCrypt.Net.BCrypt.HashPassword(request.Password),
             DisplayName = request.DisplayName?.Trim(),
+            Role = isFirstUser ? ServerRole.Owner : ServerRole.Member,
         };
 
         _db.Users.Add(user);
@@ -80,6 +84,9 @@ public class AuthController : ControllerBase
         if (user is null || !BCrypt.Net.BCrypt.Verify(request.Password, user.PasswordHash))
             return Unauthorized(new ErrorResponse("Invalid username or password."));
 
+        if (user.IsBanned)
+            return Unauthorized(new ErrorResponse("Your account has been banned."));
+
         user.LastSeenAt = DateTimeOffset.UtcNow;
         await _db.SaveChangesAsync();
 

src/EchoHub.Server/Controllers/ChannelsController.cs

@@ -141,8 +141,10 @@ public class ChannelsController : ControllerBase
         if (dbChannel is null)
             return NotFound(new ErrorResponse($"Channel '{channelName}' does not exist."));
 
-        if (dbChannel.CreatedByUserId != Guid.Parse(userIdClaim))
-            return StatusCode(403, new ErrorResponse("Only the channel creator can delete the channel."));
+        var userId = Guid.Parse(userIdClaim);
+        var caller = await _db.Users.FindAsync(userId);
+        if (dbChannel.CreatedByUserId != userId && (caller is null || caller.Role < ServerRole.Admin))
+            return StatusCode(403, new ErrorResponse("Only the channel creator or an admin can delete the channel."));
 
         _db.Channels.Remove(dbChannel);
         await _db.SaveChangesAsync();

src/EchoHub.Server/Controllers/ModerationController.cs

@@ -0,0 +1,228 @@
+using System.Security.Claims;
+using EchoHub.Core.Contracts;
+using EchoHub.Core.DTOs;
+using EchoHub.Core.Models;
+using EchoHub.Server.Data;
+using EchoHub.Server.Services;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.RateLimiting;
+using Microsoft.EntityFrameworkCore;
+
+namespace EchoHub.Server.Controllers;
+
+[ApiController]
+[Route("api/moderation")]
+[Authorize]
+[EnableRateLimiting("general")]
+public class ModerationController : ControllerBase
+{
+    private readonly EchoHubDbContext _db;
+    private readonly IChatService _chatService;
+    private readonly PresenceTracker _presenceTracker;
+    private readonly IEnumerable<IChatBroadcaster> _broadcasters;
+
+    public ModerationController(
+        EchoHubDbContext db,
+        IChatService chatService,
+        PresenceTracker presenceTracker,
+        IEnumerable<IChatBroadcaster> broadcasters)
+    {
+        _db = db;
+        _chatService = chatService;
+        _presenceTracker = presenceTracker;
+        _broadcasters = broadcasters;
+    }
+
+    [HttpPost("role")]
+    public async Task<IActionResult> AssignRole([FromBody] AssignRoleRequest request)
+    {
+        var (caller, error) = await GetCallerAsync(ServerRole.Admin);
+        if (error is not null) return error;
+
+        if (request.Role == ServerRole.Owner)
+            return BadRequest(new ErrorResponse("Cannot assign the Owner role."));
+
+        var target = await _db.Users.FirstOrDefaultAsync(u => u.Username == request.Username.ToLowerInvariant());
+        if (target is null)
+            return NotFound(new ErrorResponse($"User '{request.Username}' not found."));
+
+        if (target.Role == ServerRole.Owner)
+            return BadRequest(new ErrorResponse("Cannot change the server owner's role."));
+
+        if (request.Role >= caller!.Role)
+            return BadRequest(new ErrorResponse("Cannot assign a role equal to or above your own."));
+
+        target.Role = request.Role;
+        await _db.SaveChangesAsync();
+
+        return Ok(new { Message = $"{target.Username} is now {request.Role}." });
+    }
+
+    [HttpPost("kick/{username}")]
+    public async Task<IActionResult> KickUser(string username, [FromBody] KickRequest? request = null)
+    {
+        var (caller, error) = await GetCallerAsync(ServerRole.Mod);
+        if (error is not null) return error;
+
+        var target = await _db.Users.FirstOrDefaultAsync(u => u.Username == username.ToLowerInvariant());
+        if (target is null)
+            return NotFound(new ErrorResponse($"User '{username}' not found."));
+
+        if (target.Role >= caller!.Role)
+            return BadRequest(new ErrorResponse("Cannot kick a user with equal or higher role."));
+
+        // Broadcast kick to all channels the user is in
+        var channels = _presenceTracker.GetChannelsForUser(target.Username);
+        foreach (var channel in channels)
+        {
+            await BroadcastToAllAsync(b => b.SendUserKickedAsync(channel, target.Username, request?.Reason));
+        }
+
+        return Ok(new { Message = $"{target.Username} has been kicked." });
+    }
+
+    [HttpPost("ban/{username}")]
+    public async Task<IActionResult> BanUser(string username, [FromBody] BanRequest? request = null)
+    {
+        var (caller, error) = await GetCallerAsync(ServerRole.Admin);
+        if (error is not null) return error;
+
+        var target = await _db.Users.FirstOrDefaultAsync(u => u.Username == username.ToLowerInvariant());
+        if (target is null)
+            return NotFound(new ErrorResponse($"User '{username}' not found."));
+
+        if (target.Role >= caller!.Role)
+            return BadRequest(new ErrorResponse("Cannot ban a user with equal or higher role."));
+
+        target.IsBanned = true;
+        await _db.SaveChangesAsync();
+
+        await BroadcastToAllAsync(b => b.SendUserBannedAsync(target.Username, request?.Reason));
+
+        return Ok(new { Message = $"{target.Username} has been banned." });
+    }
+
+    [HttpPost("unban/{username}")]
+    public async Task<IActionResult> UnbanUser(string username)
+    {
+        var (_, error) = await GetCallerAsync(ServerRole.Admin);
+        if (error is not null) return error;
+
+        var target = await _db.Users.FirstOrDefaultAsync(u => u.Username == username.ToLowerInvariant());
+        if (target is null)
+            return NotFound(new ErrorResponse($"User '{username}' not found."));
+
+        target.IsBanned = false;
+        await _db.SaveChangesAsync();
+
+        return Ok(new { Message = $"{target.Username} has been unbanned." });
+    }
+
+    [HttpPost("mute/{username}")]
+    public async Task<IActionResult> MuteUser(string username, [FromBody] MuteRequest? request = null)
+    {
+        var (caller, error) = await GetCallerAsync(ServerRole.Mod);
+        if (error is not null) return error;
+
+        var target = await _db.Users.FirstOrDefaultAsync(u => u.Username == username.ToLowerInvariant());
+        if (target is null)
+            return NotFound(new ErrorResponse($"User '{username}' not found."));
+
+        if (target.Role >= caller!.Role)
+            return BadRequest(new ErrorResponse("Cannot mute a user with equal or higher role."));
+
+        target.IsMuted = true;
+        target.MutedUntil = request?.DurationMinutes is > 0
+            ? DateTimeOffset.UtcNow.AddMinutes(request.DurationMinutes.Value)
+            : null;
+        await _db.SaveChangesAsync();
+
+        var durationText = request?.DurationMinutes is > 0 ? $" for {request.DurationMinutes} minutes" : "";
+        return Ok(new { Message = $"{target.Username} has been muted{durationText}." });
+    }
+
+    [HttpPost("unmute/{username}")]
+    public async Task<IActionResult> UnmuteUser(string username)
+    {
+        var (_, error) = await GetCallerAsync(ServerRole.Mod);
+        if (error is not null) return error;
+
+        var target = await _db.Users.FirstOrDefaultAsync(u => u.Username == username.ToLowerInvariant());
+        if (target is null)
+            return NotFound(new ErrorResponse($"User '{username}' not found."));
+
+        target.IsMuted = false;
+        target.MutedUntil = null;
+        await _db.SaveChangesAsync();
+
+        return Ok(new { Message = $"{target.Username} has been unmuted." });
+    }
+
+    [HttpDelete("messages/{messageId:guid}")]
+    public async Task<IActionResult> DeleteMessage(Guid messageId)
+    {
+        var (_, error) = await GetCallerAsync(ServerRole.Mod);
+        if (error is not null) return error;
+
+        var message = await _db.Messages
+            .Include(m => m.Channel)
+            .FirstOrDefaultAsync(m => m.Id == messageId);
+
+        if (message is null)
+            return NotFound(new ErrorResponse("Message not found."));
+
+        var channelName = message.Channel!.Name;
+        _db.Messages.Remove(message);
+        await _db.SaveChangesAsync();
+
+        await BroadcastToAllAsync(b => b.SendMessageDeletedAsync(channelName, messageId));
+
+        return Ok(new { Message = "Message deleted." });
+    }
+
+    [HttpDelete("channels/{channel}/nuke")]
+    public async Task<IActionResult> NukeChannel(string channel)
+    {
+        var (_, error) = await GetCallerAsync(ServerRole.Mod);
+        if (error is not null) return error;
+
+        var channelName = channel.ToLowerInvariant().Trim();
+        var dbChannel = await _db.Channels.FirstOrDefaultAsync(c => c.Name == channelName);
+        if (dbChannel is null)
+            return NotFound(new ErrorResponse($"Channel '{channelName}' does not exist."));
+
+        var messages = await _db.Messages.Where(m => m.ChannelId == dbChannel.Id).ToListAsync();
+        _db.Messages.RemoveRange(messages);
+        await _db.SaveChangesAsync();
+
+        await BroadcastToAllAsync(b => b.SendChannelNukedAsync(channelName));
+
+        return Ok(new { Message = $"All messages in #{channelName} have been cleared." });
+    }
+
+    private async Task<(User? Caller, IActionResult? Error)> GetCallerAsync(ServerRole minimumRole)
+    {
+        var userIdClaim = User.FindFirstValue(ClaimTypes.NameIdentifier);
+        if (userIdClaim is null)
+            return (null, Unauthorized(new ErrorResponse("Authentication required.")));
+
+        var caller = await _db.Users.FindAsync(Guid.Parse(userIdClaim));
+        if (caller is null)
+            return (null, Unauthorized(new ErrorResponse("User not found.")));
+
+        if (caller.Role < minimumRole)
+            return (null, StatusCode(403, new ErrorResponse($"Requires {minimumRole} role or higher.")));
+
+        return (caller, null);
+    }
+
+    private async Task BroadcastToAllAsync(Func<IChatBroadcaster, Task> action)
+    {
+        foreach (var broadcaster in _broadcasters)
+        {
+            try { await action(broadcaster); }
+            catch { /* logged by broadcaster */ }
+        }
+    }
+}

src/EchoHub.Server/Controllers/UsersController.cs

@@ -120,6 +120,7 @@ public class UsersController : ControllerBase
         user.AvatarAscii,
         user.Status,
         user.StatusMessage,
+        user.Role,
         user.CreatedAt,
         user.LastSeenAt);
 }

src/EchoHub.Server/Data/EchoHubDbContext.cs

@@ -34,6 +34,7 @@ public class EchoHubDbContext : DbContext
             entity.Property(u => u.NicknameColor).HasMaxLength(7);
             entity.Property(u => u.AvatarAscii).HasMaxLength(10000);
             entity.Property(u => u.StatusMessage).HasMaxLength(100);
+            entity.Property(u => u.Role).HasConversion<int>();
         });
 
         modelBuilder.Entity<Channel>(entity =>

src/EchoHub.Server/Data/Migrations/20260219162414_AddModerationRoles.Designer.cs

@@ -0,0 +1,222 @@
+// <auto-generated />
+using System;
+using EchoHub.Server.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace EchoHub.Server.Data.Migrations
+{
+    [DbContext(typeof(EchoHubDbContext))]
+    [Migration("20260219162414_AddModerationRoles")]
+    partial class AddModerationRoles
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "10.0.3");
+
+            modelBuilder.Entity("EchoHub.Core.Models.Channel", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<long>("CreatedAt")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<Guid>("CreatedByUserId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Topic")
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name")
+                        .IsUnique();
+
+                    b.ToTable("Channels");
+                });
+
+            modelBuilder.Entity("EchoHub.Core.Models.Message", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AttachmentFileName")
+                        .HasMaxLength(255)
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AttachmentUrl")
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("ChannelId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Content")
+                        .IsRequired()
+                        .HasMaxLength(2000)
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("SenderUserId")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("SenderUsername")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT");
+
+                    b.Property<long>("SentAt")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("Type")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ChannelId");
+
+                    b.HasIndex("SentAt");
+
+                    b.ToTable("Messages");
+                });
+
+            modelBuilder.Entity("EchoHub.Core.Models.RefreshToken", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<long>("CreatedAt")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<long>("ExpiresAt")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<long?>("RevokedAt")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("TokenHash")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("TEXT");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TokenHash");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("RefreshTokens");
+                });
+
+            modelBuilder.Entity("EchoHub.Core.Models.User", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("AvatarAscii")
+                        .HasMaxLength(10000)
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Bio")
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT");
+
+                    b.Property<long>("CreatedAt")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("DisplayName")
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT");
+
+                    b.Property<bool>("IsBanned")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("IsMuted")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<long>("LastSeenAt")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<long?>("MutedUntil")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("NicknameColor")
+                        .HasMaxLength(7)
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("Role")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("StatusMessage")
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Username")
+                        .IsUnique();
+
+                    b.ToTable("Users");
+                });
+
+            modelBuilder.Entity("EchoHub.Core.Models.Message", b =>
+                {
+                    b.HasOne("EchoHub.Core.Models.Channel", "Channel")
+                        .WithMany("Messages")
+                        .HasForeignKey("ChannelId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Channel");
+                });
+
+            modelBuilder.Entity("EchoHub.Core.Models.RefreshToken", b =>
+                {
+                    b.HasOne("EchoHub.Core.Models.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("EchoHub.Core.Models.Channel", b =>
+                {
+                    b.Navigation("Messages");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

src/EchoHub.Server/Data/Migrations/20260219162414_AddModerationRoles.cs

@@ -0,0 +1,61 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace EchoHub.Server.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddModerationRoles : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<bool>(
+                name: "IsBanned",
+                table: "Users",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: false);
+
+            migrationBuilder.AddColumn<bool>(
+                name: "IsMuted",
+                table: "Users",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: false);
+
+            migrationBuilder.AddColumn<long>(
+                name: "MutedUntil",
+                table: "Users",
+                type: "INTEGER",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "Role",
+                table: "Users",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: 0);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "IsBanned",
+                table: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "IsMuted",
+                table: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "MutedUntil",
+                table: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "Role",
+                table: "Users");
+        }
+    }
+}

src/EchoHub.Server/Data/Migrations/EchoHubDbContextModelSnapshot.cs

@@ -144,9 +144,18 @@ namespace EchoHub.Server.Data.Migrations
                         .HasMaxLength(100)
                         .HasColumnType("TEXT");
 
+                    b.Property<bool>("IsBanned")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<bool>("IsMuted")
+                        .HasColumnType("INTEGER");
+
                     b.Property<long>("LastSeenAt")
                         .HasColumnType("INTEGER");
 
+                    b.Property<long?>("MutedUntil")
+                        .HasColumnType("INTEGER");
+
                     b.Property<string>("NicknameColor")
                         .HasMaxLength(7)
                         .HasColumnType("TEXT");
@@ -155,6 +164,9 @@ namespace EchoHub.Server.Data.Migrations
                         .IsRequired()
                         .HasColumnType("TEXT");
 
+                    b.Property<int>("Role")
+                        .HasColumnType("INTEGER");
+
                     b.Property<int>("Status")
                         .HasColumnType("INTEGER");
 

src/EchoHub.Server/Services/ChatService.cs

@@ -72,7 +72,8 @@ public class ChatService : IChatService
                     user.DisplayName,
                     user.NicknameColor,
                     UserStatus.Invisible,
-                    user.StatusMessage);
+                    user.StatusMessage,
+                    user.Role);
 
                 await BroadcastToAllAsync(b => b.SendUserStatusChangedAsync(channelsBeforeDisconnect, presence));
             }
@@ -139,6 +140,21 @@ public class ChatService : IChatService
 
         var sender = await db.Users.FindAsync(userId);
 
+        // Check mute status
+        if (sender is not null && sender.IsMuted)
+        {
+            if (sender.MutedUntil.HasValue && sender.MutedUntil.Value <= DateTimeOffset.UtcNow)
+            {
+                sender.IsMuted = false;
+                sender.MutedUntil = null;
+                await db.SaveChangesAsync();
+            }
+            else
+            {
+                return "You are muted and cannot send messages.";
+            }
+        }
+
         var message = new Message
         {
             Id = Guid.NewGuid(),
@@ -203,7 +219,8 @@ public class ChatService : IChatService
             user.DisplayName,
             user.NicknameColor,
             status,
-            statusMessage);
+            statusMessage,
+            user.Role);
 
         var channels = _presenceTracker.GetChannelsForUser(username);
         await BroadcastToAllAsync(b => b.SendUserStatusChangedAsync(channels, presence));
@@ -226,7 +243,8 @@ public class ChatService : IChatService
                 u.DisplayName,
                 u.NicknameColor,
                 u.Status,
-                u.StatusMessage))
+                u.StatusMessage,
+                u.Role))
             .ToListAsync();
     }
 
@@ -264,7 +282,7 @@ public class ChatService : IChatService
         return new UserProfileDto(
             user.Id, user.Username, user.DisplayName, user.Bio,
             user.NicknameColor, user.AvatarAscii, user.Status,
-            user.StatusMessage, user.CreatedAt, user.LastSeenAt);
+            user.StatusMessage, user.Role, user.CreatedAt, user.LastSeenAt);
     }
 
     public async Task<(string? Topic, bool Exists)> GetChannelTopicAsync(string channelName)

src/EchoHub.Server/Services/ImageToAsciiService.cs

@@ -8,47 +8,72 @@ namespace EchoHub.Server.Services;
 
 public class ImageToAsciiService
 {
-    private static readonly char[] AsciiChars = " .:-=+*#%@".ToCharArray();
-
-    public string ConvertToAscii(Stream imageStream, int width = HubConstants.AsciiArtWidth, int height = HubConstants.AsciiArtHeight)
+    /// <summary>
+    /// Converts an image to ASCII art using half-block characters (▀▄█) with
+    /// 24-bit ANSI foreground and background colors for 2x vertical resolution.
+    /// Each character cell represents two vertical pixels.
+    /// </summary>
+    public string ConvertToAscii(Stream imageStream, int width = HubConstants.AsciiArtWidth, int height = HubConstants.AsciiArtHeightHalfBlock)
     {
         using var image = Image.Load<Rgba32>(imageStream);
 
+        // Ensure height is even for pair processing
+        if (height % 2 != 0) height++;
+
         image.Mutate(x => x.Resize(width, height));
 
         var sb = new StringBuilder();
 
-        byte lastR = 0, lastG = 0, lastB = 0;
+        for (int y = 0; y < image.Height; y += 2)
+        {
+            byte lastFgR = 0, lastFgG = 0, lastFgB = 0;
+            byte lastBgR = 0, lastBgG = 0, lastBgB = 0;
             bool hasLastColor = false;
 
-        for (int y = 0; y < image.Height; y++)
-        {
             for (int x = 0; x < image.Width; x++)
             {
-                var pixel = image[x, y];
-                var brightness = 0.299 * pixel.R + 0.587 * pixel.G + 0.114 * pixel.B;
+                var topPixel = image[x, y];
+                var bottomPixel = (y + 1 < image.Height) ? image[x, y + 1] : topPixel;
 
-                // Map brightness (0-255) to ASCII char index
-                var index = (int)((brightness / 255.0) * (AsciiChars.Length - 1));
+                byte fgR, fgG, fgB, bgR, bgG, bgB;
+                char blockChar;
 
-                // Emit ANSI 24-bit color only when it changes
-                if (!hasLastColor || pixel.R != lastR || pixel.G != lastG || pixel.B != lastB)
+                if (topPixel.R == bottomPixel.R && topPixel.G == bottomPixel.G && topPixel.B == bottomPixel.B)
                 {
-                    sb.Append($"\x1b[38;2;{pixel.R};{pixel.G};{pixel.B}m");
-                    lastR = pixel.R;
-                    lastG = pixel.G;
-                    lastB = pixel.B;
-                    hasLastColor = true;
+                    // Both pixels same color — full block
+                    fgR = topPixel.R; fgG = topPixel.G; fgB = topPixel.B;
+                    bgR = topPixel.R; bgG = topPixel.G; bgB = topPixel.B;
+                    blockChar = '\u2588'; // █
+                }
+                else
+                {
+                    // Top pixel = foreground, bottom pixel = background, upper half block
+                    fgR = topPixel.R; fgG = topPixel.G; fgB = topPixel.B;
+                    bgR = bottomPixel.R; bgG = bottomPixel.G; bgB = bottomPixel.B;
+                    blockChar = '\u2580'; // ▀
                 }
 
-                sb.Append(AsciiChars[index]);
+                // Emit color codes only when they change
+                bool fgChanged = !hasLastColor || fgR != lastFgR || fgG != lastFgG || fgB != lastFgB;
+                bool bgChanged = !hasLastColor || bgR != lastBgR || bgG != lastBgG || bgB != lastBgB;
+
+                if (fgChanged)
+                    sb.Append($"\x1b[38;2;{fgR};{fgG};{fgB}m");
+                if (bgChanged)
+                    sb.Append($"\x1b[48;2;{bgR};{bgG};{bgB}m");
+
+                sb.Append(blockChar);
+
+                lastFgR = fgR; lastFgG = fgG; lastFgB = fgB;
+                lastBgR = bgR; lastBgG = bgG; lastBgB = bgB;
+                hasLastColor = true;
             }
 
             // Reset color at end of line
             sb.Append("\x1b[0m");
             hasLastColor = false;
 
-            if (y < image.Height - 1)
+            if (y + 2 < image.Height)
             {
                 sb.AppendLine();
             }

src/EchoHub.Server/Services/SignalRBroadcaster.cs

@@ -54,6 +54,18 @@ public class SignalRBroadcaster : IChatBroadcaster
         return HubContext.Clients.Clients(connections).UserStatusChanged(presence);
     }
 
+    public Task SendUserKickedAsync(string channelName, string username, string? reason)
+        => HubContext.Clients.Group(channelName).UserKicked(channelName, username, reason);
+
+    public Task SendUserBannedAsync(string username, string? reason)
+        => HubContext.Clients.All.UserBanned(username, reason);
+
+    public Task SendMessageDeletedAsync(string channelName, Guid messageId)
+        => HubContext.Clients.Group(channelName).MessageDeleted(channelName, messageId);
+
+    public Task SendChannelNukedAsync(string channelName)
+        => HubContext.Clients.Group(channelName).ChannelNuked(channelName);
+
     public Task SendErrorAsync(string connectionId, string message)
     {
         if (connectionId.StartsWith("irc-"))