complete restructure

vibe_bot/commands/chat.py

@@ -0,0 +1,19 @@
+"""Custom-bot chat has no command of its own, so this group registers nothing.
+
+A message like ``!alfred hello`` is matched against the bot-name cache in
+``vibe_bot.app.on_message`` and dispatched to ``ChatService.handle``; ordinary
+``!`` messages fall through to the commands registered by the other groups.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from discord.ext import commands
+
+    from vibe_bot.app import App
+
+
+def register(bot: commands.Bot, app: App) -> None:
+    """Register no commands: custom-bot chat flows through ``on_message``."""