Define code+LLM collaboration protocol for group chat participation:
- Code layer: no @mention gate, forward all msgs to LLM
- LLM layer: output __SILENT__ (discard) or __REPLY__ (send)
- Documented in MEMORY.md (LLM prompt) and AgentsMeeting (shared ref)
- Update xmpp_bot.py to remove @mention gate
If xmpp_connected=false, force restart immediately instead of
waiting 10 minutes for message timeout. This catches the most
common failure mode: process alive but XMPP dead.