feat: add blockchain state and balance endpoints with multi-chain support

- Add GET /state endpoint to blockchain RPC router for chain state information
- Add GET /rpc/getBalance/{address} endpoint for account balance queries
- Add GET /rpc/head endpoint to retrieve current chain head block
- Add GET /rpc/transactions endpoint for latest transaction listing
- Add chain-specific wallet balance endpoint to wallet daemon
- Add blockchain state CLI command with --all-chains flag for multi-chain queries

cli/aitbc_cli/commands/marketplace.py

@@ -6,6 +6,7 @@ import json
 import asyncio
 from typing import Optional, List, Dict, Any
 from ..utils import output, error, success
+import os
 
 
 @click.group()