refactor: improve gossip broker cleanup and enhance CLI wallet transaction handling

- Refactor _InProcessBroadcast.subscribe to use asynccontextmanager for cleaner resource cleanup
- Remove manual release callback in _InProcessSubscriber
- Update file-based wallet send to submit transactions via blockchain RPC
- Fetch balance and nonce from chain before sending transactions
- Add tx_hash and status tracking to local transaction history
- Enhance run_subprocess to support additional kwargs and return Comp

test_wallet.py

@@ -0,0 +1,22 @@
+import json
+
+wallet_data = {
+    "name": "test_wallet",
+    "type": "hd",
+    "address": "aitbc1genesis",
+    "private_key": "dummy",
+    "public_key": "dummy",
+    "encrypted": False,
+    "transactions": [],
+    "balance": 1000000
+}
+
+import os
+import pathlib
+
+wallet_dir = pathlib.Path("/root/.aitbc/wallets")
+wallet_dir.mkdir(parents=True, exist_ok=True)
+wallet_path = wallet_dir / "test_wallet.json"
+
+with open(wallet_path, "w") as f:
+    json.dump(wallet_data, f)