feat: Add GitHub Actions CI for PR protection

- Add CI workflow with Python (ruff lint, security tests) and UI (ESLint, TypeScript, build) jobs
- Add ruff, mypy, pytest to requirements.txt
- Add pyproject.toml with ruff configuration
- Fix import sorting across Python files (ruff --fix)
- Fix test_security.py expectations to match actual security policy
- Remove invalid 'eof' command from ALLOWED_COMMANDS

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

server/services/process_manager.py

@@ -14,11 +14,10 @@ import sys
 import threading
 from datetime import datetime
 from pathlib import Path
-from typing import Literal, Callable, Awaitable, Set
+from typing import Awaitable, Callable, Literal, Set
 
 import psutil
 
-
 logger = logging.getLogger(__name__)
 
 # Patterns for sensitive data that should be redacted from output