feat(matrix-bridge-dagi): add room mapping, ingress loop, synapse setup (PR-M1.2 + PR-M1.3)

PR-M1.2 — room-to-agent mapping:
- adds room_mapping.py: parse BRIDGE_ROOM_MAP (format: agent:!room_id:server)
- RoomMappingConfig with O(1) room→agent lookup, agent allowlist check
- /bridge/mappings endpoint (read-only ops summary, no secrets)
- health endpoint now includes mappings_count
- 21 tests for parsing, validation, allowlist, summary

PR-M1.3 — Matrix ingress loop:
- adds ingress.py: MatrixIngressLoop asyncio task
- sync_poll → extract → dedupe → _invoke_gateway (POST /v1/invoke)
- gateway payload: agent_id, node_id, message, metadata (transport, room_id, event_id, sender)
- exponential backoff on errors (2s..60s)
- joins all mapped rooms at startup
- metric callbacks: on_message_received, on_gateway_error
- graceful shutdown via asyncio.Event
- 5 ingress tests (invoke, dedupe, callbacks, empty-map idle)

Synapse setup (docker-compose.synapse-node1.yml):
- fixed volume: bind mount ./synapse-data instead of named volume
- added port mapping 127.0.0.1:8008:8008

Synapse running on NODA1 (localhost:8008), bot @dagi_bridge:daarion.space created,
room !QwHczWXgefDHBEVkTH:daarion.space created, all 4 values in .env on NODA1.

Made-with: Cursor

docker-compose.synapse-node1.yml

@@ -20,8 +20,10 @@ services:
     restart: unless-stopped
     environment:
       - SYNAPSE_CONFIG_PATH=/data/homeserver.yaml
+    ports:
+      - "127.0.0.1:8008:8008"
     volumes:
-      - synapse-data:/data
+      - ./synapse-data:/data
     depends_on:
       synapse-db:
         condition: service_healthy
@@ -60,7 +62,6 @@ services:
       - dagi-network
 
 volumes:
-  synapse-data:
   synapse-db-data:
 
 networks: