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

apps/blockchain-node/src/aitbc_chain/network/discovery.py

@@ -75,9 +75,9 @@ class P2PDiscovery:
         """Add bootstrap node for initial connection"""
         self.bootstrap_nodes.append((address, port))
     
-    def generate_node_id(self, address: str, port: int, public_key: str) -> str:
-        """Generate unique node ID from address, port, and public key"""
-        content = f"{address}:{port}:{public_key}"
+    def generate_node_id(self, hostname: str, address: str, port: int, public_key: str) -> str:
+        """Generate unique node ID from hostname, address, port, and public key"""
+        content = f"{hostname}:{address}:{port}:{public_key}"
         return hashlib.sha256(content.encode()).hexdigest()
     
     async def start_discovery(self):