feat: add password protection for channels

- Updated IChatService to include password parameter in JoinChannelAsync method.
- Modified ChannelDto and related models to support password functionality.
- Implemented password handling in ChannelService for channel creation and membership validation.
- Enhanced IrcCommandHandler to manage channel join requests with passwords.
- Added ChannelPasswordDialog for user input when joining protected channels.
- Created database migration to add PasswordHash column to Channels table.
- Updated tests to cover new password functionality in channel joining and management.

docs/articles/architecture.md

@@ -52,7 +52,7 @@ Terminal.Gui v2 TUI application:
 
 - **UI**: Main window, dialogs, chat renderer with ANSI color support
 - **Services**: API client with automatic token refresh, SignalR connection wrapper, audio playback (NetCoreAudio), automatic update checker (AlwaysUpToDate)
-- **Themes**: 13 built-in color themes (including transparent theme with true terminal transparency)
+- **Themes**: 14 built-in color themes (including transparent dark/light themes with true terminal transparency)
 - **Config**: Client configuration management with session persistence ("Remember Me" refresh tokens)
 
 ## Communication

docs/todo.md

@@ -3,7 +3,7 @@
 - [ ] fix the chat trailing; when user scrolls up, and somebody sends a message – the chat instantly "teleports" to the very bottom
 - [x] disable the autorun of files (maybe keep for mp4? gotta do some sec research on it)
 - [x] when user creates a new channel, he gets moved to that channel; but the userlist does not refresh the state on that – it refreshes when user re-enters the channel again
-- [ ] password protected rooms
+- [x] password protected rooms
 - [ ] better audio lib, current one (NetCoreAudio) does not support seek or other audio actions
 - [ ] Use options pattern for both client & server
   - ref: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-10.0