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

cli/aitbc_cli/utils/subprocess.py

@@ -1,29 +1,29 @@
 import subprocess
 import sys
-from typing import List, Optional, Union
+from typing import List, Optional, Union, Any
 from . import error, output
 
-def run_subprocess(cmd: List[str], check: bool = True, capture_output: bool = True, shell: bool = False) -> Optional[str]:
+def run_subprocess(cmd: List[str], check: bool = True, capture_output: bool = True, shell: bool = False, **kwargs: Any) -> Optional[Union[str, subprocess.CompletedProcess]]:
     """Run a subprocess command safely with logging"""
     try:
         if shell:
             # When shell=True, cmd should be a string
             cmd_str = " ".join(cmd) if isinstance(cmd, list) else cmd
-            result = subprocess.run(cmd_str, shell=True, check=check, capture_output=capture_output, text=True)
+            result = subprocess.run(cmd_str, shell=True, check=check, capture_output=capture_output, text=True, **kwargs)
         else:
-            result = subprocess.run(cmd, check=check, capture_output=capture_output, text=True)
+            result = subprocess.run(cmd, check=check, capture_output=capture_output, text=True, **kwargs)
             
         if capture_output:
             return result.stdout.strip()
-        return None
+        return result
         
     except subprocess.CalledProcessError as e:
         error(f"Command failed with exit code {e.returncode}")
-        if capture_output and e.stderr:
+        if capture_output and getattr(e, 'stderr', None):
             print(e.stderr, file=sys.stderr)
         if check:
             sys.exit(e.returncode)
-        return None
+        return getattr(e, 'stdout', None) if capture_output else None
     except Exception as e:
         error(f"Failed to execute command: {e}")
         if check: