feat: migrate wallet daemon and CLI to use centralized aitbc package utilities

- Migrate simple_daemon.py from mock data to real keystore and blockchain RPC integration
- Add httpx for async HTTP client in wallet daemon
- Implement real wallet listing from keystore directory
- Implement blockchain balance queries via RPC
- Update CLI to use aitbc.AITBCHTTPClient instead of requests
- Add aitbc imports: constants, http_client, exceptions, logging, paths, validation
- Add address and amount validation in

cli/aitbc_cli/commands/gpu_marketplace.py

@@ -12,8 +12,8 @@ import asyncio
 from datetime import datetime
 from decimal import Decimal
 from typing import Optional, List
-from cli.utils import output, error, success, info, warning
-from cli.aitbc_cli.utils.island_credentials import (
+from ..utils import output, error, success, info, warning
+from ..utils.island_credentials import (
     load_island_credentials, get_rpc_endpoint, get_chain_id,
     get_island_id, get_island_name
 )