feat: add IsPublic property to channels and enhance channel creation with visibility options

src/EchoHub.Client/AppOrchestrator.cs

@@ -212,6 +212,8 @@ public sealed class AppOrchestrator : IDisposable
                 var history = await _connection!.JoinChannelAsync(channelName);
                 InvokeUI(() =>
                 {
+                    // Add to channel list if not already there (e.g. private channels)
+                    _mainWindow.EnsureChannelInList(channelName);
                     _mainWindow.SwitchToChannel(channelName);
                     if (history.Count > 0)
                         _mainWindow.LoadHistory(channelName, history);
@@ -704,17 +706,18 @@ public sealed class AppOrchestrator : IDisposable
 
         RunAsync(async () =>
         {
-            var channel = await _apiClient!.CreateChannelAsync(result.Name, result.Topic);
+            var channel = await _apiClient!.CreateChannelAsync(result.Name, result.Topic, result.IsPublic);
             if (channel is null) return;
 
             _joinedChannels.Add(channel.Name);
             var history = await _connection!.JoinChannelAsync(channel.Name);
 
-            // Refresh the channel list
+            // Refresh the channel list and ensure private channels show up
             var channels = await _apiClient.GetChannelsAsync();
             InvokeUI(() =>
             {
                 _mainWindow.SetChannels(channels);
+                _mainWindow.EnsureChannelInList(channel.Name);
                 _mainWindow.SwitchToChannel(channel.Name);
                 if (history.Count > 0)
                     _mainWindow.LoadHistory(channel.Name, history);

src/EchoHub.Client/Program.cs

@@ -4,6 +4,8 @@ using EchoHub.Client.Themes;
 using Microsoft.Extensions.Configuration;
 using Serilog;
 using Terminal.Gui.App;
+using Terminal.Gui.Drawing;
+
 
 var appSettingsPath = Path.Combine(AppContext.BaseDirectory, "appsettings.json");
 if (!File.Exists(appSettingsPath))

src/EchoHub.Client/Services/ApiClient.cs

@@ -186,10 +186,10 @@ public sealed class ApiClient : IDisposable
         return await response.Content.ReadFromJsonAsync<MessageDto>();
     }
 
-    public async Task<ChannelDto?> CreateChannelAsync(string name, string? topic = null)
+    public async Task<ChannelDto?> CreateChannelAsync(string name, string? topic = null, bool isPublic = true)
     {
         EnsureAuthenticated();
-        var request = new CreateChannelRequest(name, topic);
+        var request = new CreateChannelRequest(name, topic, isPublic);
         var response = await AuthenticatedRequestAsync(() =>
             _http.PostAsJsonAsync("/api/channels", request));
         await EnsureSuccessAsync(response);

src/EchoHub.Client/UI/ChatRenderer.cs

@@ -90,13 +90,23 @@ public partial class ChatLine
     }
 
     /// <summary>
-    /// Parse a string containing ANSI 24-bit color escape codes into colored segments.
+    /// Returns true if a line contains color tags (new format or legacy ANSI).
-    /// 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)
+    public static bool HasColorTags(string text) =>
+        text.Contains("{F:") || text.Contains("{B:") || text.Contains("{X}") || text.Contains('\x1b');
+
+    /// <summary>
+    /// Parse a string containing color tags into colored segments.
+    /// Supports the new printable format ({F:RRGGBB}, {B:RRGGBB}, {X})
+    /// and legacy ANSI format (\x1b[38;2;R;G;Bm, \x1b[48;2;R;G;Bm, \x1b[0m).
+    /// </summary>
+    public static ChatLine FromColoredText(string text, Attribute? defaultAttr = null)
     {
+        // Detect which format is used and pick the right regex
+        var regex = text.Contains('\x1b') ? AnsiColorRegex() : ColorTagRegex();
+        bool isAnsi = text.Contains('\x1b');
+
         var segments = new List<ChatSegment>();
-        var regex = AnsiColorRegex();
         int lastIndex = 0;
         Color? currentFg = null;
         Color? currentBg = null;
@@ -111,52 +121,76 @@ public partial class ChatLine
             return new Attribute(fg, bg);
         }
 
-        foreach (Match match in regex.Matches(ansiText))
+        foreach (Match match in regex.Matches(text))
         {
-            // Add any text before this escape sequence
             if (match.Index > lastIndex)
             {
-                var text = ansiText[lastIndex..match.Index];
+                var t = text[lastIndex..match.Index];
-                if (text.Length > 0)
+                if (t.Length > 0)
-                    segments.Add(new ChatSegment(text, BuildAttr()));
+                    segments.Add(new ChatSegment(t, BuildAttr()));
             }
 
-            // Parse the escape sequence
+            if (isAnsi)
-            if (match.Groups[1].Value == "0")
             {
-                // Reset
+                // Legacy ANSI format
-                currentFg = null;
+                if (match.Groups[1].Value == "0")
-                currentBg = null;
+                {
+                    currentFg = null;
+                    currentBg = null;
+                }
+                else if (match.Groups[2].Success)
+                {
+                    var r = int.Parse(match.Groups[3].Value);
+                    var g = int.Parse(match.Groups[4].Value);
+                    var b = int.Parse(match.Groups[5].Value);
+                    if (match.Groups[2].Value == "38;2")
+                        currentFg = new Color(r, g, b);
+                    else
+                        currentBg = new Color(r, g, b);
+                }
             }
-            else if (match.Groups[2].Success)
+            else
             {
-                var r = int.Parse(match.Groups[3].Value);
+                // New printable tag format: {F:RRGGBB}, {B:RRGGBB}, {X}
-                var g = int.Parse(match.Groups[4].Value);
+                if (match.Groups[6].Success)
-                var b = int.Parse(match.Groups[5].Value);
+                {
-
+                    // Reset {X}
-                if (match.Groups[2].Value == "38;2")
+                    currentFg = null;
-                    currentFg = new Color(r, g, b);
+                    currentBg = null;
-                else // 48;2
+                }
-                    currentBg = new Color(r, g, b);
+                else if (match.Groups[7].Success)
+                {
+                    var hex = match.Groups[8].Value;
+                    var r = Convert.ToInt32(hex[..2], 16);
+                    var g = Convert.ToInt32(hex[2..4], 16);
+                    var b = Convert.ToInt32(hex[4..6], 16);
+                    if (match.Groups[7].Value == "F")
+                        currentFg = new Color(r, g, b);
+                    else
+                        currentBg = new Color(r, g, b);
+                }
             }
 
             lastIndex = match.Index + match.Length;
         }
 
-        // Add remaining text
+        if (lastIndex < text.Length)
-        if (lastIndex < ansiText.Length)
         {
-            var text = ansiText[lastIndex..];
+            var t = text[lastIndex..];
-            if (text.Length > 0)
+            if (t.Length > 0)
-                segments.Add(new ChatSegment(text, BuildAttr()));
+                segments.Add(new ChatSegment(t, BuildAttr()));
         }
 
         return segments.Count > 0 ? new ChatLine(segments) : new ChatLine("");
     }
 
-    // Matches: \x1b[0m (reset), \x1b[38;2;R;G;Bm (fg), or \x1b[48;2;R;G;Bm (bg)
+    // Legacy: \x1b[0m, \x1b[38;2;R;G;Bm, \x1b[48;2;R;G;Bm
     [GeneratedRegex(@"\x1b\[(?:(0)|(?:(38;2|48;2);(\d{1,3});(\d{1,3});(\d{1,3})))m")]
     private static partial Regex AnsiColorRegex();
+
+    // New: {X} (reset), {F:RRGGBB} (foreground), {B:RRGGBB} (background)
+    [GeneratedRegex(@"\{(?:(X)|(?:(F|B):([0-9A-Fa-f]{6})))\}")]
+    private static partial Regex ColorTagRegex();
 }
 
 /// <summary>

src/EchoHub.Client/UI/CreateChannelDialog.cs

@@ -4,7 +4,7 @@ using Terminal.Gui.ViewBase;
 
 namespace EchoHub.Client.UI;
 
-public record CreateChannelResult(string Name, string? Topic);
+public record CreateChannelResult(string Name, string? Topic, bool IsPublic);
 
 public sealed class CreateChannelDialog
 {
@@ -12,7 +12,7 @@ public sealed class CreateChannelDialog
     {
         CreateChannelResult? result = null;
 
-        var dialog = new Dialog { Title = "Create Channel", Width = 50, Height = 12 };
+        var dialog = new Dialog { Title = "Create Channel", Width = 50, Height = 14 };
 
         var nameLabel = new Label { Text = "Name:", X = 1, Y = 1 };
         var nameField = new TextField { X = 10, Y = 1, Width = Dim.Fill(2) };
@@ -20,11 +20,19 @@ public sealed class CreateChannelDialog
         var topicLabel = new Label { Text = "Topic:", X = 1, Y = 3 };
         var topicField = new TextField { X = 10, Y = 3, Width = Dim.Fill(2) };
 
+        var publicCheckbox = new CheckBox
+        {
+            Text = "Public (visible to all users)",
+            X = 1,
+            Y = 5,
+            Value = CheckState.Checked
+        };
+
         var hintLabel = new Label
         {
             Text = "Lowercase letters, digits, hyphens, underscores (2-100 chars)",
             X = 1,
-            Y = 5,
+            Y = 7,
         };
 
         var createButton = new Button
@@ -32,14 +40,14 @@ public sealed class CreateChannelDialog
             Text = "Create",
             IsDefault = true,
             X = Pos.Center() - 10,
-            Y = 7
+            Y = 9
         };
 
         var cancelButton = new Button
         {
             Text = "Cancel",
             X = Pos.Center() + 5,
-            Y = 7
+            Y = 9
         };
 
         createButton.Accepting += (s, e) =>
@@ -55,7 +63,8 @@ public sealed class CreateChannelDialog
             if (string.IsNullOrWhiteSpace(topic))
                 topic = null;
 
-            result = new CreateChannelResult(name, topic);
+            var isPublic = publicCheckbox.Value == CheckState.Checked;
+            result = new CreateChannelResult(name, topic, isPublic);
             e.Handled = true;
             app.RequestStop();
         };
@@ -67,7 +76,7 @@ public sealed class CreateChannelDialog
             app.RequestStop();
         };
 
-        dialog.Add(nameLabel, nameField, topicLabel, topicField, hintLabel, createButton, cancelButton);
+        dialog.Add(nameLabel, nameField, topicLabel, topicField, publicCheckbox, hintLabel, createButton, cancelButton);
 
         nameField.SetFocus();
         app.Run(dialog);

src/EchoHub.Client/UI/MainWindow.cs

@@ -582,6 +582,20 @@ public sealed class MainWindow : Runnable
         RefreshChannelList();
     }
 
+    /// <summary>
+    /// Ensure a channel exists in the left panel list (used for private channels joined via /join).
+    /// </summary>
+    public void EnsureChannelInList(string channelName)
+    {
+        if (_channelNames.Contains(channelName))
+            return;
+
+        _channelNames.Add(channelName);
+        if (!_channelMessages.ContainsKey(channelName))
+            _channelMessages[channelName] = [];
+        RefreshChannelList();
+    }
+
     /// <summary>
     /// Update the topic for a specific channel.
     /// </summary>
@@ -838,10 +852,10 @@ public sealed class MainWindow : Runnable
                 {
                     foreach (var artLine in message.Content.Split('\n'))
                     {
-                        // Parse ANSI color codes from colored ASCII art
+                        // Parse color tags from colored ASCII art
                         var trimmed = artLine.TrimEnd('\r');
-                        if (trimmed.Contains('\x1b'))
+                        if (ChatLine.HasColorTags(trimmed))
-                            lines.Add(ChatLine.FromAnsi("       " + trimmed));
+                            lines.Add(ChatLine.FromColoredText("       " + trimmed));
                         else
                             lines.Add(new ChatLine($"       {trimmed}"));
                     }

src/EchoHub.Core/DTOs/ChatDtos.cs

@@ -17,6 +17,7 @@ public record ChannelDto(
     Guid Id,
     string Name,
     string? Topic,
+    bool IsPublic,
     int MessageCount,
     DateTimeOffset CreatedAt);
 
@@ -30,7 +31,7 @@ public record UserDto(
 
 public record SendMessageRequest(string ChannelName, string Content);
 
-public record CreateChannelRequest(string Name, string? Topic = null);
+public record CreateChannelRequest(string Name, string? Topic = null, bool IsPublic = true);
 
 public record UpdateTopicRequest(string? Topic);
 

src/EchoHub.Core/Models/Channel.cs

@@ -5,6 +5,7 @@ public class Channel
     public Guid Id { get; set; }
     public required string Name { get; set; }
     public string? Topic { get; set; }
+    public bool IsPublic { get; set; } = true;
     public DateTimeOffset CreatedAt { get; set; } = DateTimeOffset.UtcNow;
     public Guid CreatedByUserId { get; set; }
 

src/EchoHub.Server.Irc/IrcMessageFormatter.cs

@@ -1,10 +1,11 @@
 using System.Text;
+using System.Text.RegularExpressions;
 using EchoHub.Core.DTOs;
 using EchoHub.Core.Models;
 
 namespace EchoHub.Server.Irc;
 
-public static class IrcMessageFormatter
+public static partial class IrcMessageFormatter
 {
     private const int MaxIrcLineContentBytes = 400;
 
@@ -33,7 +34,7 @@ public static class IrcMessageFormatter
                 {
                     var trimmed = line.TrimEnd('\r');
                     if (trimmed.Length > 0)
-                        lines.Add($"{prefix} PRIVMSG {ircChannel} :{trimmed}");
+                        lines.Add($"{prefix} PRIVMSG {ircChannel} :{ColorTagsToAnsi(trimmed)}");
                 }
                 break;
 
@@ -45,6 +46,35 @@ public static class IrcMessageFormatter
         return lines;
     }
 
+    /// <summary>
+    /// Convert printable color tags ({F:RRGGBB}, {B:RRGGBB}, {X}) to ANSI escape codes for IRC clients.
+    /// Also passes through content that already uses ANSI codes unchanged.
+    /// </summary>
+    public static string ColorTagsToAnsi(string text)
+    {
+        if (!text.Contains('{'))
+            return text;
+
+        return ColorTagRegex().Replace(text, match =>
+        {
+            if (match.Groups[1].Success) // {X} reset
+                return "\x1b[0m";
+            if (match.Groups[2].Success) // {F:RRGGBB} or {B:RRGGBB}
+            {
+                var hex = match.Groups[3].Value;
+                var r = Convert.ToInt32(hex[..2], 16);
+                var g = Convert.ToInt32(hex[2..4], 16);
+                var b = Convert.ToInt32(hex[4..6], 16);
+                var code = match.Groups[2].Value == "F" ? "38" : "48";
+                return $"\x1b[{code};2;{r};{g};{b}m";
+            }
+            return match.Value;
+        });
+    }
+
+    [GeneratedRegex(@"\{(?:(X)|(?:(F|B):([0-9A-Fa-f]{6})))\}")]
+    private static partial Regex ColorTagRegex();
+
     /// <summary>
     /// Split a message into chunks of approximately maxBytes (UTF-8), at word boundaries.
     /// </summary>

src/EchoHub.Server/Controllers/ChannelsController.cs

@@ -43,9 +43,10 @@ public class ChannelsController : ControllerBase
         offset = Math.Max(0, offset);
         limit = Math.Clamp(limit, 1, 100);
 
-        var total = await _db.Channels.CountAsync();
+        var query = _db.Channels.Where(c => c.IsPublic);
+        var total = await query.CountAsync();
 
-        var channels = await _db.Channels
+        var channels = await query
             .OrderBy(c => c.Name)
             .Skip(offset)
             .Take(limit)
@@ -53,6 +54,7 @@ public class ChannelsController : ControllerBase
                 c.Id,
                 c.Name,
                 c.Topic,
+                c.IsPublic,
                 c.Messages.Count,
                 c.CreatedAt))
             .ToListAsync();
@@ -83,14 +85,16 @@ public class ChannelsController : ControllerBase
             Id = Guid.NewGuid(),
             Name = channelName,
             Topic = request.Topic?.Trim(),
+            IsPublic = request.IsPublic,
             CreatedByUserId = Guid.Parse(userIdClaim),
         };
 
         _db.Channels.Add(channel);
         await _db.SaveChangesAsync();
 
-        var dto = new ChannelDto(channel.Id, channel.Name, channel.Topic, 0, channel.CreatedAt);
+        var dto = new ChannelDto(channel.Id, channel.Name, channel.Topic, channel.IsPublic, 0, channel.CreatedAt);
-        await _chatService.BroadcastChannelUpdatedAsync(dto);
+        if (channel.IsPublic)
+            await _chatService.BroadcastChannelUpdatedAsync(dto);
 
         return Created($"/api/channels/{channelName}", dto);
     }
@@ -118,7 +122,7 @@ public class ChannelsController : ControllerBase
         await _db.SaveChangesAsync();
 
         var messageCount = await _db.Messages.CountAsync(m => m.ChannelId == dbChannel.Id);
-        var dto = new ChannelDto(dbChannel.Id, dbChannel.Name, dbChannel.Topic, messageCount, dbChannel.CreatedAt);
+        var dto = new ChannelDto(dbChannel.Id, dbChannel.Name, dbChannel.Topic, dbChannel.IsPublic, messageCount, dbChannel.CreatedAt);
         await _chatService.BroadcastChannelUpdatedAsync(dto, channelName);
 
         return Ok(dto);

src/EchoHub.Server/Data/Migrations/20260219172834_AddChannelIsPublic.Designer.cs

@@ -0,0 +1,225 @@
+// <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("20260219172834_AddChannelIsPublic")]
+    partial class AddChannelIsPublic
+    {
+        /// <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<bool>("IsPublic")
+                        .HasColumnType("INTEGER");
+
+                    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/20260219172834_AddChannelIsPublic.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace EchoHub.Server.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddChannelIsPublic : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<bool>(
+                name: "IsPublic",
+                table: "Channels",
+                type: "INTEGER",
+                nullable: false,
+                defaultValue: false);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "IsPublic",
+                table: "Channels");
+        }
+    }
+}

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

@@ -29,6 +29,9 @@ namespace EchoHub.Server.Data.Migrations
                     b.Property<Guid>("CreatedByUserId")
                         .HasColumnType("TEXT");
 
+                    b.Property<bool>("IsPublic")
+                        .HasColumnType("INTEGER");
+
                     b.Property<string>("Name")
                         .IsRequired()
                         .HasMaxLength(100)

src/EchoHub.Server/Services/ImageToAsciiService.cs

@@ -21,8 +21,10 @@ public class ImageToAsciiService
 
     /// <summary>
     /// Converts an image to ASCII art using half-block characters (▀▄█) with
-    /// 24-bit ANSI foreground and background colors for 2x vertical resolution.
+    /// printable color tags for 2x vertical resolution.
     /// Each character cell represents two vertical pixels.
+    /// Format: {F:RRGGBB} foreground, {B:RRGGBB} background, {X} reset.
+    /// Uses only printable ASCII — no terminal escape bytes.
     /// </summary>
     public string ConvertToAscii(Stream imageStream, int width = HubConstants.AsciiArtWidth, int height = HubConstants.AsciiArtHeightHalfBlock)
     {
@@ -51,27 +53,24 @@ public class ImageToAsciiService
 
                 if (topPixel.R == bottomPixel.R && topPixel.G == bottomPixel.G && topPixel.B == bottomPixel.B)
                 {
-                    // 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'; // ▀
                 }
 
-                // 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($"\x1b[38;2;{fgR};{fgG};{fgB}m");
+                    sb.Append($"{{F:{fgR:X2}{fgG:X2}{fgB:X2}}}");
                 if (bgChanged)
-                    sb.Append($"\x1b[48;2;{bgR};{bgG};{bgB}m");
+                    sb.Append($"{{B:{bgR:X2}{bgG:X2}{bgB:X2}}}");
 
                 sb.Append(blockChar);
 
@@ -80,8 +79,7 @@ public class ImageToAsciiService
                 hasLastColor = true;
             }
 
-            // Reset color at end of line
+            sb.Append("{X}");
-            sb.Append("\x1b[0m");
             hasLastColor = false;
 
             if (y + 2 < image.Height)