The server never proactively offered GMCP or MSDP to clients, so
telnetlib3 logged "cannot send MSDP without negotiation" every second.
Now the server sends WILL GMCP and WILL MSDP on connection, and
send_msdp_vitals checks negotiation state before attempting to send.
Implements Phase 7 foundation:
- gmcp.py module with package builders for Char.Vitals, Char.Status,
Room.Info, Room.Map, and MSDP vitals
- Player helper methods send_gmcp() and send_msdp() for convenience
- Full test coverage for all GMCP/MSDP functions and edge cases
