Expose IPFS swarm port 4002 for P2P connectivity

Uses port 4002 externally (L1 uses 4001) to avoid conflict
when both run on same server.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.yml

@@ -19,6 +19,9 @@ services:
 
   ipfs:
     image: ipfs/kubo:latest
+    ports:
+      - "4002:4001"      # Swarm TCP (4002 external, L1 uses 4001)
+      - "4002:4001/udp"  # Swarm UDP
     volumes:
       - ipfs_data:/data/ipfs
     networks: