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.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");