network: add hub registration, Redis persistence, and federated mesh join protocol

- Change default P2P port from 7070 to 8001 in config and .env.example
- Add redis_url configuration option for hub persistence (default: redis://localhost:6379)
- Implement DNS-based hub registration/unregistration via HTTPS API endpoints
- Add Redis persistence for hub registrations with 1-hour TTL
- Add island join request/response protocol with member list and blockchain credentials
- Add GPU marketplace tracking (offers, bids, providers) in hub manager
- Add

scripts/utils/validate-requirements.sh

@@ -143,7 +143,7 @@ check_network() {
     echo -e "\n📋 Checking Network Requirements..."
     
     # Check if required ports are available
-    REQUIRED_PORTS=(8000 8001 8002 8003 8010 8011 8012 8013 8014 8015 8016)
+    REQUIRED_PORTS=(8000 8001 8003 8007 8008 8010 8011 8012 8013 8014 8015)
     OCCUPIED_PORTS=()
     
     for port in "${REQUIRED_PORTS[@]}"; do