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/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;