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>

tests/test_core.py

@@ -0,0 +1,92 @@
+"""Tests for the core plugin."""
+
+import asyncio
+import importlib.util
+import sys
+from unittest.mock import MagicMock
+
+# -- Load plugin module directly ---------------------------------------------
+
+_spec = importlib.util.spec_from_file_location("core", "plugins/core.py")
+_mod = importlib.util.module_from_spec(_spec)
+sys.modules["core"] = _mod
+_spec.loader.exec_module(_mod)
+
+
+# -- Fakes -------------------------------------------------------------------
+
+
+class _FakeRegistry:
+    def __init__(self):
+        self._bots: dict = {}
+
+
+class _FakeBot:
+    def __init__(self, *, mumble: bool = False):
+        self.replied: list[str] = []
+        self.registry = _FakeRegistry()
+        self.nick = "derp"
+        self._receive_sound = False
+        if mumble:
+            self._mumble = MagicMock()
+
+    async def reply(self, message, text: str) -> None:
+        self.replied.append(text)
+
+
+def _make_listener():
+    """Create a fake listener bot (merlin) with _receive_sound=True."""
+    listener = _FakeBot(mumble=True)
+    listener.nick = "merlin"
+    listener._receive_sound = True
+    return listener
+
+
+class _Msg:
+    def __init__(self, text="!deaf"):
+        self.text = text
+        self.nick = "Alice"
+        self.target = "0"
+        self.is_channel = True
+        self.prefix = "Alice"
+
+
+# -- Tests -------------------------------------------------------------------
+
+
+class TestDeafCommand:
+    def test_deaf_targets_listener(self):
+        """!deaf toggles the listener bot (merlin), not the calling bot."""
+        bot = _FakeBot(mumble=True)
+        listener = _make_listener()
+        bot.registry._bots = {"derp": bot, "merlin": listener}
+        listener._mumble.users.myself.get.return_value = False
+        msg = _Msg(text="!deaf")
+        asyncio.run(_mod.cmd_deaf(bot, msg))
+        listener._mumble.users.myself.deafen.assert_called_once()
+        assert any("merlin" in r and "deafened" in r for r in bot.replied)
+
+    def test_deaf_toggle_off(self):
+        bot = _FakeBot(mumble=True)
+        listener = _make_listener()
+        bot.registry._bots = {"derp": bot, "merlin": listener}
+        listener._mumble.users.myself.get.return_value = True
+        msg = _Msg(text="!deaf")
+        asyncio.run(_mod.cmd_deaf(bot, msg))
+        listener._mumble.users.myself.undeafen.assert_called_once()
+        listener._mumble.users.myself.unmute.assert_called_once()
+        assert any("merlin" in r and "undeafened" in r for r in bot.replied)
+
+    def test_deaf_non_mumble_silent(self):
+        bot = _FakeBot(mumble=False)
+        msg = _Msg(text="!deaf")
+        asyncio.run(_mod.cmd_deaf(bot, msg))
+        assert bot.replied == []
+
+    def test_deaf_fallback_no_listener(self):
+        """Falls back to calling bot when no listener is registered."""
+        bot = _FakeBot(mumble=True)
+        bot._mumble.users.myself.get.return_value = False
+        msg = _Msg(text="!deaf")
+        asyncio.run(_mod.cmd_deaf(bot, msg))
+        bot._mumble.users.myself.deafen.assert_called_once()