Add TS6 clientinit version middleware and fix playNext retry bug

clientinit compatibility:
- Analyzed @honeybbq/teamspeak-client's clientinit: it already sends a
  clean 14-field payload without problematic fields (no badges,
  integrations, security_hash, etc.)
- The key difference vs NeteaseTSBot is client_version: our library
  sends 3.5.3, NeteaseTSBot sends 3.6.2. TS6 servers may reject
  older versions.
- Add ts6-compat.ts with CommandMiddleware that patches clientinit
  to use version 3.6.2 + matching ECDSA signature when connecting
  to detected TS6 servers
- Middleware is automatically applied when detectedProtocol === "ts6"

Pre-existing bug fix:
- Fix playNext() in instance.ts where successful retry still fell
  through to player.stop(), killing the just-started playback

https://claude.ai/code/session_016WhH58avUD9xy2dgADJgTh

src/bot/instance.ts

@@ -494,14 +494,19 @@ export class BotInstance extends EventEmitter {
       this.voteSkipUsers.clear();
       const next = this.queue.next();
       if (next) {
-        const ok = await this.resolveAndPlay(next);
-        if (!ok) {
+        let started = await this.resolveAndPlay(next);
+        if (!started) {
           // Skip to next if URL resolve fails (up to 3 retries)
           for (let i = 0; i < 3; i++) {
             const retry = this.queue.next();
             if (!retry) break;
-            if (await this.resolveAndPlay(retry)) break;
+            if (await this.resolveAndPlay(retry)) {
+              started = true;
+              break;
+            }
           }
+        }
+        if (!started) {
           this.player.stop();
         }
       } else {