feat(matrix-bridge-dagi): support N rooms in BRIDGE_ROOM_MAP, reject duplicate room_id (M2.0)

Made-with: Cursor

services/matrix-bridge-dagi/app/room_mapping.py

@@ -1,5 +1,5 @@
 """
-Room-to-Agent Mapping — Phase M1
+Room-to-Agent Mapping — Phase M2.0 (N rooms, 1 agent per room)
 
 Parses BRIDGE_ROOM_MAP env var and provides:
   - room_id → agent_id lookup
@@ -148,6 +148,16 @@ def parse_room_map(raw: str, allowed_agents: FrozenSet[str]) -> RoomMappingConfi
     if errors:
         raise ValueError(f"BRIDGE_ROOM_MAP parse errors: {'; '.join(errors)}")
 
+    # M2.0: fail fast on duplicate room_id (1 room must map to exactly 1 agent)
+    seen_rooms: Dict[str, str] = {}
+    for m in mappings:
+        if m.room_id in seen_rooms:
+            raise ValueError(
+                f"Duplicate room_id {m.room_id!r}: already bound to agent "
+                f"{seen_rooms[m.room_id]!r}, cannot rebind to {m.agent_id!r}"
+            )
+        seen_rooms[m.room_id] = m.agent_id
+
     config = RoomMappingConfig(mappings=mappings, allowed_agents=allowed_agents)
     logger.info(
         "Room mapping loaded: %d entries, allowed_agents=%s",