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_plugin.py

@@ -36,6 +36,20 @@ class TestDecorators:
         assert handler._derp_event == "PRIVMSG"
 
 
+    def test_command_decorator_aliases(self):
+        @command("skip", help="skip track", aliases=["next", "s"])
+        async def handler(bot, msg):
+            pass
+
+        assert handler._derp_aliases == ["next", "s"]
+
+    def test_command_decorator_aliases_default(self):
+        @command("ping", help="ping")
+        async def handler(bot, msg):
+            pass
+
+        assert handler._derp_aliases == []
+
     def test_command_decorator_admin(self):
         @command("secret", help="admin only", admin=True)
         async def handler(bot, msg):
@@ -208,6 +222,46 @@ class TestRegistry:
         assert registry.commands["secret"].admin is True
         assert registry.commands["public"].admin is False
 
+    def test_load_plugin_aliases(self, tmp_path: Path):
+        plugin_file = tmp_path / "aliased.py"
+        plugin_file.write_text(textwrap.dedent("""\
+            from derp.plugin import command
+
+            @command("skip", help="Skip track", aliases=["next", "s"])
+            async def cmd_skip(bot, msg):
+                pass
+        """))
+
+        registry = PluginRegistry()
+        count = registry.load_plugin(plugin_file)
+        assert count == 3  # primary + 2 aliases
+        assert "skip" in registry.commands
+        assert "next" in registry.commands
+        assert "s" in registry.commands
+        # Aliases point to the same callback
+        assert registry.commands["next"].callback is registry.commands["skip"].callback
+        assert registry.commands["s"].callback is registry.commands["skip"].callback
+        # Alias help text references the primary command
+        assert registry.commands["next"].help == "alias for !skip"
+
+    def test_unload_removes_aliases(self, tmp_path: Path):
+        plugin_file = tmp_path / "aliased.py"
+        plugin_file.write_text(textwrap.dedent("""\
+            from derp.plugin import command
+
+            @command("skip", help="Skip track", aliases=["next"])
+            async def cmd_skip(bot, msg):
+                pass
+        """))
+
+        registry = PluginRegistry()
+        registry.load_plugin(plugin_file)
+        assert "next" in registry.commands
+
+        registry.unload_plugin("aliased")
+        assert "skip" not in registry.commands
+        assert "next" not in registry.commands
+
     def test_load_plugin_stores_path(self, tmp_path: Path):
         plugin_file = tmp_path / "pathed.py"
         plugin_file.write_text(textwrap.dedent("""\
@@ -677,6 +731,71 @@ class TestChannelFilter:
         assert bot._plugin_allowed("encode", "&local") is False
 
 
+class TestAliasDispatch:
+    """Test alias fallback in _dispatch_command."""
+
+    @staticmethod
+    def _make_bot_with_alias(alias_name: str, target_cmd: str) -> tuple[Bot, list]:
+        """Create a Bot with a command and an alias pointing to it."""
+        config = {
+            "server": {"host": "localhost", "port": 6667, "tls": False,
+                       "nick": "test", "user": "test", "realname": "test"},
+            "bot": {"prefix": "!", "channels": [], "plugins_dir": "plugins"},
+        }
+        registry = PluginRegistry()
+        called = []
+
+        async def _handler(bot, msg):
+            called.append(msg.text)
+
+        registry.register_command(target_cmd, _handler, plugin="test")
+        bot = Bot("test", config, registry)
+        bot.conn = _FakeConnection()
+        bot.state.set("alias", alias_name, target_cmd)
+        return bot, called
+
+    def test_alias_resolves_command(self):
+        """An alias triggers the target command handler."""
+        bot, called = self._make_bot_with_alias("s", "skip")
+        msg = Message(raw="", prefix="nick!u@h", nick="nick",
+                      command="PRIVMSG", params=["#ch", "!s"], tags={})
+
+        async def _run():
+            bot._dispatch_command(msg)
+            await asyncio.sleep(0.05)  # let spawned task run
+
+        asyncio.run(_run())
+        assert len(called) == 1
+
+    def test_alias_ignored_when_command_exists(self):
+        """Direct command match takes priority over alias."""
+        bot, called = self._make_bot_with_alias("skip", "stop")
+        # "skip" is both a real command and an alias to "stop"; real wins
+        msg = Message(raw="", prefix="nick!u@h", nick="nick",
+                      command="PRIVMSG", params=["#ch", "!skip"], tags={})
+
+        async def _run():
+            bot._dispatch_command(msg)
+            await asyncio.sleep(0.05)
+
+        asyncio.run(_run())
+        assert len(called) == 1
+        # Handler was the "skip" handler, not "stop"
+
+    def test_no_alias_no_crash(self):
+        """Unknown command with no alias silently returns."""
+        config = {
+            "server": {"host": "localhost", "port": 6667, "tls": False,
+                       "nick": "test", "user": "test", "realname": "test"},
+            "bot": {"prefix": "!", "channels": [], "plugins_dir": "plugins"},
+        }
+        bot = Bot("test", config, PluginRegistry())
+        bot.conn = _FakeConnection()
+        msg = Message(raw="", prefix="nick!u@h", nick="nick",
+                      command="PRIVMSG", params=["#ch", "!nonexistent"], tags={})
+        bot._dispatch_command(msg)  # should not raise
+
+
 class TestSplitUtf8:
     """Test UTF-8 safe message splitting."""