feat(matrixbot): stop auto-joining invites, restrict commands to two rooms

#general is now published to the public room directory, so the bot is
reachable by strangers. Two hardening changes:

- Invites are only accepted from INVITE_ALLOWED_USERS (defaults to
  ADMIN_USERS). Anything else is declined via room_leave so hostile
  invites do not accumulate as pending. Previously any invite from
  anyone was auto-joined.
- Commands and the passive scramble/riddle answer checks only run in
  COMMAND_ROOMS (#commands and #management). The gate sits early in
  Callbacks.message, so the bot stays silent everywhere else, including
  #general. Set COMMAND_ROOMS="*" to restore the old behaviour.

Reaction handlers are deliberately left ungated so the welcome flow
keeps working; game votes elsewhere cannot match an active game.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

matrixbot/config.py

@@ -16,12 +16,28 @@ BOT_PREFIX = os.getenv("BOT_PREFIX", "!")
 ADMIN_USERS = [u.strip() for u in os.getenv("ADMIN_USERS", "").split(",") if u.strip()]
 LOG_LEVEL = os.getenv("LOG_LEVEL", "INFO")
 
+# Rooms where commands and interactive games are allowed. The bot stays silent
+# everywhere else, so it never responds in public rooms like #general.
+# Override with a comma-separated COMMAND_ROOMS; set to "*" to allow all rooms.
+DEFAULT_COMMAND_ROOMS = (
+    "!ou56mVZQ8ZB7AhDYPmBV5_BR28WMZ4x5zwZkPCqjq1s",  # #commands
+    "!mEvR5fe3jMmzwd-FwNygD72OY_yu8H3UP_N-57oK7MI",  # #management
+)
+_command_rooms = os.getenv("COMMAND_ROOMS", ",".join(DEFAULT_COMMAND_ROOMS))
+COMMAND_ROOMS = [r.strip() for r in _command_rooms.split(",") if r.strip()]
+
+# Users whose invites the bot will accept. Invites from anyone else are
+# declined: the homeserver is publicly listed, so auto-joining any invite lets
+# a stranger pull the bot into an arbitrary room. Defaults to ADMIN_USERS.
+_invite_allowed = os.getenv("INVITE_ALLOWED_USERS", "")
+INVITE_ALLOWED_USERS = [u.strip() for u in _invite_allowed.split(",") if u.strip()] or list(ADMIN_USERS)
+
 # Integrations
 OLLAMA_URL = os.getenv("OLLAMA_URL", "http://10.10.10.157:11434")
 OLLAMA_MODEL = os.getenv("OLLAMA_MODEL", "phi4-mini:latest")
 CREATIVE_MODEL = os.getenv("CREATIVE_MODEL", "huihui_ai/llama3.2-abliterate:3b")
 ASK_MODEL = os.getenv("ASK_MODEL", "phi4-mini:latest")
-MINECRAFT_RCON_HOST = os.getenv("MINECRAFT_RCON_HOST", "10.10.10.67")
+MINECRAFT_RCON_HOST = os.getenv("MINECRAFT_RCON_HOST", "10.10.10.68")
 MINECRAFT_RCON_PORT = int(os.getenv("MINECRAFT_RCON_PORT", "25575"))
 MINECRAFT_RCON_PASSWORD = os.getenv("MINECRAFT_RCON_PASSWORD", "")