The protbot sent "DSGN:\x00" as the sign request type, but the server
strips the last 3 characters as a version suffix. Send "DSGN:041"
(ZZ client mode 41) to match the real client format.
The entrance channel entry parser read 14 bytes for remaining fields
but the server writes 18 bytes (9 uint16, not 7), causing a panic
when parsing the server list.
The channel server panicked on disconnect when a session had no
decompressed save data (e.g. protbot or early client disconnect).
Guard Save() against nil decompSave.
Also fix docker-compose volume mount for Postgres 18 which changed
its data directory layout.
Copy MHBridge into the Erupe module as cmd/protbot/ so it can be
built, tested, and maintained alongside the server. The bot
implements the full sign → entrance → channel login flow and
supports lobby entry, chat, session setup, and quest enumeration.
The conn/ package keeps its own Blowfish crypto primitives to avoid
importing erupe-ce/config (which requires a config file at init).
