feat: voice profiles, rubberband FX, per-bot plugin filtering

- Add rubberband package to container for pitch-shifting FX
- Split FX chain: rubberband CLI for pitch, ffmpeg for filters
- Configurable voice profile (voice, fx, piper params) in [voice]
- Extra bots inherit voice config (minus trigger) for own TTS
- Greeting is voice-only, spoken directly by the greeting bot
- Per-bot only_plugins/except_plugins filtering on Mumble
- Alias plugin, core plugin tests

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

plugins/core.py

@@ -174,6 +174,34 @@ async def cmd_admins(bot, message):
     await bot.reply(message, " | ".join(parts))
 
 
+@command("deaf", help="Toggle voice listener deaf on Mumble")
+async def cmd_deaf(bot, message):
+    """Toggle the voice listener's deaf state on Mumble.
+
+    Targets the bot with ``receive_sound = true`` (merlin) so that
+    deafening stops ducking without affecting the music bot's playback.
+    """
+    # Find the listener bot (receive_sound=true) among registered peers
+    listener = None
+    bots = getattr(bot.registry, "_bots", {})
+    for peer in bots.values():
+        if getattr(peer, "_receive_sound", False):
+            listener = peer
+            break
+    mumble = getattr(listener or bot, "_mumble", None)
+    if mumble is None:
+        return
+    myself = mumble.users.myself
+    name = getattr(listener, "nick", "bot")
+    if myself.get("self_deaf", False):
+        myself.undeafen()
+        myself.unmute()
+        await bot.reply(message, f"{name}: undeafened")
+    else:
+        myself.deafen()
+        await bot.reply(message, f"{name}: deafened")
+
+
 @command("state", help="Inspect plugin state: !state <list|get|del|clear> ...", admin=True)
 async def cmd_state(bot, message):
     """Manage the plugin state store.