refactor: flatten CLI directory structure - remove 'box in a box'

BEFORE:
/opt/aitbc/cli/
├── aitbc_cli/                    # Python package (box in a box)
│   ├── commands/
│   ├── main.py
│   └── ...
├── setup.py

AFTER:
/opt/aitbc/cli/                    # Flat structure
├── commands/                      # Direct access
├── main.py                        # Direct access
├── auth/
├── config/
├── core/
├── models/
├── utils/
├── plugins.py
└── setup.py

CHANGES MADE:
- Moved all files from aitbc_cli/ to cli/ root
- Fixed all relative imports (from . to absolute imports)
- Updated setup.py entry point: aitbc_cli.main → main
- Added CLI directory to Python path in entry script
- Simplified deployment.py to remove dependency on deleted core.deployment
- Fixed import paths in all command files
- Recreated virtual environment with new structure

BENEFITS:
- Eliminated 'box in a box' nesting
- Simpler directory structure
- Direct access to all modules
- Cleaner imports
- Easier maintenance and development
- CLI works with both 'python main.py' and 'aitbc' commands

cli/utils/subprocess.py

@@ -0,0 +1,31 @@
+import subprocess
+import sys
+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, **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, **kwargs)
+        else:
+            result = subprocess.run(cmd, check=check, capture_output=capture_output, text=True, **kwargs)
+            
+        if capture_output:
+            return result.stdout.strip()
+        return result
+        
+    except subprocess.CalledProcessError as e:
+        error(f"Command failed with exit code {e.returncode}")
+        if capture_output and getattr(e, 'stderr', None):
+            print(e.stderr, file=sys.stderr)
+        if check:
+            sys.exit(e.returncode)
+        return getattr(e, 'stdout', None) if capture_output else None
+    except Exception as e:
+        error(f"Failed to execute command: {e}")
+        if check:
+            sys.exit(1)
+        return None