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.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);
 }