feat: add BiliBili audio source integration

Implement BiliBiliProvider for video-as-audio playback using direct
BiliBili API calls (search, video info, DASH audio URL extraction).
Add QR code login support and cookie persistence. Update FFmpeg to
send Referer header for BiliBili CDN URLs. Extend platform union type
to "netease" | "qq" | "bilibili" across all interfaces. Add -b flag
for chat commands and B站 badge in web UI.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/bot/instance.ts

@@ -22,6 +22,7 @@ export interface BotInstanceOptions {
   tsOptions: TS3ClientOptions;
   neteaseProvider: MusicProvider;
   qqProvider: MusicProvider;
+  bilibiliProvider: MusicProvider;
   database: BotDatabase;
   config: BotConfig;
   logger: Logger;
@@ -49,6 +50,7 @@ export class BotInstance extends EventEmitter {
   private queue: PlayQueue;
   private neteaseProvider: MusicProvider;
   private qqProvider: MusicProvider;
+  private bilibiliProvider: MusicProvider;
   private database: BotDatabase;
   private config: BotConfig;
   private logger: Logger;
@@ -62,6 +64,7 @@ export class BotInstance extends EventEmitter {
     this.name = options.name;
     this.neteaseProvider = options.neteaseProvider;
     this.qqProvider = options.qqProvider;
+    this.bilibiliProvider = options.bilibiliProvider;
     this.database = options.database;
     this.config = options.config;
     this.logger = options.logger.child({ botId: this.id });
@@ -207,12 +210,15 @@ export class BotInstance extends EventEmitter {
     }
   }
 
-  getProviderFor(platform: "netease" | "qq"): MusicProvider {
+  getProviderFor(platform: "netease" | "qq" | "bilibili"): MusicProvider {
+    if (platform === "bilibili") return this.bilibiliProvider;
     return platform === "qq" ? this.qqProvider : this.neteaseProvider;
   }
 
-  private getProvider(useQQ: boolean): MusicProvider {
-    return useQQ ? this.qqProvider : this.neteaseProvider;
+  private getProvider(flags: Set<string>): MusicProvider {
+    if (flags.has("b")) return this.bilibiliProvider;
+    if (flags.has("q")) return this.qqProvider;
+    return this.neteaseProvider;
   }
 
   /** Resolve URL for a song and start playing it. Skips to next if URL fails. */
@@ -245,7 +251,7 @@ export class BotInstance extends EventEmitter {
 
   private async cmdPlay(cmd: ParsedCommand): Promise<string> {
     if (!cmd.args) return "Usage: !play <song name or URL>";
-    const provider = this.getProvider(cmd.flags.has("q"));
+    const provider = this.getProvider(cmd.flags);
     const result = await provider.search(cmd.args, 1);
     if (result.songs.length === 0)
       return `No results found for: ${cmd.args}`;
@@ -262,7 +268,7 @@ export class BotInstance extends EventEmitter {
 
   private async cmdAdd(cmd: ParsedCommand): Promise<string> {
     if (!cmd.args) return "Usage: !add <song name>";
-    const provider = this.getProvider(cmd.flags.has("q"));
+    const provider = this.getProvider(cmd.flags);
     const result = await provider.search(cmd.args, 1);
     if (result.songs.length === 0)
       return `No results found for: ${cmd.args}`;
@@ -367,7 +373,7 @@ export class BotInstance extends EventEmitter {
 
   private async cmdPlaylist(cmd: ParsedCommand): Promise<string> {
     if (!cmd.args) return "Usage: !playlist <playlist ID or URL>";
-    const provider = this.getProvider(cmd.flags.has("q"));
+    const provider = this.getProvider(cmd.flags);
     const id = this.extractId(cmd.args);
     const songs = await provider.getPlaylistSongs(id);
     if (songs.length === 0) return "Playlist is empty or not found";
@@ -384,7 +390,7 @@ export class BotInstance extends EventEmitter {
 
   private async cmdAlbum(cmd: ParsedCommand): Promise<string> {
     if (!cmd.args) return "Usage: !album <album ID>";
-    const provider = this.getProvider(cmd.flags.has("q"));
+    const provider = this.getProvider(cmd.flags);
     const songs = await provider.getAlbumSongs(cmd.args);
     if (songs.length === 0) return "Album is empty or not found";
 
@@ -437,7 +443,7 @@ export class BotInstance extends EventEmitter {
   private async cmdLyrics(): Promise<string> {
     const song = this.queue.current();
     if (!song) return "Nothing is playing";
-    const provider = this.getProvider(song.platform === "qq");
+    const provider = this.getProviderFor(song.platform);
     const lyrics = await provider.getLyrics(song.id);
     if (lyrics.length === 0) return "No lyrics available";
     const lines = lyrics.slice(0, 10).map((l) => l.text);
@@ -461,6 +467,7 @@ export class BotInstance extends EventEmitter {
       "TSMusicBot Commands:",
       `${p}play <song>  — Search and play`,
       `${p}play -q <song> — Search from QQ Music`,
+      `${p}play -b <song> — Search from BiliBili`,
       `${p}add <song>   — Add to queue`,
       `${p}pause/resume — Pause/resume`,
       `${p}next/prev    — Next/previous`,