feat: add chain_id parameter to get_addresses RPC endpoint

🔧 Address Listing Enhancement:
• Add optional chain_id parameter to /addresses endpoint
• Use get_chain_id() helper for chain_id resolution with settings default
• Support multi-chain address queries with proper chain filtering
• Maintain backward compatibility with existing API consumers

apps/blockchain-node/src/aitbc_chain/rpc/router.py

@@ -420,7 +420,7 @@ async def get_address_details(address: str, limit: int = 20, offset: int = 0) ->
 
 
 @router.get("/addresses", summary="Get list of active addresses")
-async def get_addresses(limit: int = 20, offset: int = 0, min_balance: int = 0) -> Dict[str, Any]:
+async def get_addresses(limit: int = 20, offset: int = 0, min_balance: int = 0, chain_id: str = None) -> Dict[str, Any]:
     metrics_registry.increment("rpc_get_addresses_total")
     start = time.perf_counter()
     
@@ -430,6 +430,8 @@ async def get_addresses(limit: int = 20, offset: int = 0, min_balance: int = 0)
     if offset < 0:
         raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="offset must be non-negative")
     
+    chain_id = get_chain_id(chain_id)
+    
     with session_scope() as session:
         # Get addresses with balance >= min_balance
         addresses = session.exec(