chore: update changelog for v0.2.5 release with new features and fixes

docs/changelog/v0.2.5.md

@@ -1,4 +1,33 @@
-# v0.2.5 - IRC Gateway Fixes & Test Coverage
+# v0.2.5 - Audio Playback, File Downloads & IRC Fixes
+
+## Features
+
+### Audio Message Support
+
+- New `Audio` message type — uploaded audio files (`.mp3`, `.wav`, `.ogg`, `.flac`, `.aac`, `.m4a`, `.wma`) are automatically detected and categorized
+- TUI client renders audio messages with `♪ [Audio: filename] (Enter to play)` indicator
+- Press Enter on an audio message to play it locally via `AudioPlaybackService` (NetCoreAudio)
+- IRC gateway formats audio messages as `♪ [Audio: filename] url`
+- Server detects audio files by extension via `FileValidationHelper.IsAudioFile()`
+
+### File Downloads
+
+- Press Enter on a file message in the TUI client to download it to the local machine
+- `ApiClient.DownloadFileAsync()` streams file downloads from the server
+- File and audio messages in the chat list now show colored indicators with interaction hints
+
+### File Cleanup Service
+
+- `FileCleanupService` (BackgroundService) periodically removes old uploaded files
+- Configurable via `Storage:CleanupIntervalHours` (default 1h) and `Storage:RetentionDays` (default 30d)
+
+### Data Migration Service
+
+- `DataMigrationService` runs at startup to handle schema/data evolution
+- Ensures `#general` channel and pre-existing channels are marked public
+- Migrates legacy ANSI escape codes in image messages to printable color tags (`{F:RRGGBB}`, `{B:RRGGBB}`, `{X}`)
+- Migrates legacy single-object `EmbedJson` to array format
+- Promotes usernames listed in `Server:Admins` config to Admin role
 
 ## Fixes
 
@@ -10,5 +39,8 @@
 
 ## Infrastructure
 
-- IRC abstraction layer test suite: IrcMessage parsing, IrcMessageFormatter, IrcClientConnection, IrcCommandHandler, IrcBroadcaster (214 total tests)
+- Audio MIME types in `FilesController` (mp3, wav, ogg, flac, aac, m4a, wma)
+- Test suites: ChatLine, CommandHandler, DataMigrationService, FileValidationHelper, ImageToAsciiService, IrcMessageFormatter, JwtTokenService, LinkEmbedService
+- IRC abstraction layer test suite: IrcMessage parsing, IrcMessageFormatter, IrcClientConnection, IrcCommandHandler, IrcBroadcaster
 - Test helpers: `TestDuplexStream`, `TestIrcConnectionFactory`, `FakeChatService`, `FakeEncryptionService` for IRC unit testing without network I/O
+- 214 total tests