fix: kept file protection, skip/autoplay, TTS routing, video ID expansion

- _cleanup_track: never delete files from kept directory (data/music/)
  even when track.keep=False -- fixes kept files vanishing on replay
- !kept rm: skip to next track if removing the currently playing one
- !skip: silent (no reply), restarts play loop for autoplay on empty queue
- TTS plays through merlin's own connection instead of derp's, preventing
  choppy audio when music and TTS compete for the same output buffer
- !play recognizes bare YouTube video IDs (11-char alphanumeric)
- !kept rm <id> subcommand for removing individual kept tracks

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/voice.py

@@ -39,17 +39,6 @@ _WHISPER_URL = "http://192.168.129.9:8080/inference"
 _PIPER_URL = "http://192.168.129.9:5100/"
 
 
-def _find_voice_peer(bot):
-    """Find the voice-capable peer (the bot with 'voice' in only_plugins)."""
-    bots = getattr(bot.registry, "_bots", {})
-    for name, b in bots.items():
-        if name == bot._username:
-            continue
-        if getattr(b, "_only_plugins", None) and "voice" in b._only_plugins:
-            return b
-    return None
-
-
 # -- Per-bot state -----------------------------------------------------------
 
 
@@ -184,10 +173,8 @@ async def _flush_monitor(bot):
                     remainder = text[len(trigger):].strip()
                     if remainder:
                         log.info("voice: trigger from %s: %s", name, remainder)
-                        # Route TTS through voice-capable peer if available
-                        speaker = _find_voice_peer(bot) or bot
-                        speaker._spawn(
-                            _tts_play(speaker, remainder), name="voice-tts",
+                        bot._spawn(
+                            _tts_play(bot, remainder), name="voice-tts",
                         )
                     continue