Title: Implement minimal core framework with PL injection and update build config

Key features implemented:
- Updated package metadata and dependencies in PKG-INFO, setup files
- Added main.py entry point for backward compatibility with README launch method
- Enhanced CLI with config options, system info command, and proper signal handling
- Implemented minimal PluginManager loading only plugin-loader core plugin
- Refactored PluginLoader to follow minimal core design, removed sandbox/isolation complexity
- Updated auto-dependency plugin with safer PL injection mechanism and disabled pl_injection
- Removed legacy plugin files (firewall, frp_proxy, ftp_server, multi_lang_deploy, ops_toolbox, security_gateway) as functionality moved to core plugin system
- Improved gitignore with comprehensive ignore patterns

The changes implement a minimal core framework design where only the plugin-loader is directly loaded by the core, with all other plugins managed through the PL injection mechanism, significantly simplifying the architecture.

.gitignore

@@ -1,38 +1,39 @@
-```
-# Python cache files
+```gitignore
+# Python
 __pycache__/
-*.pyc
-*.pyo
-*.pyd
-
-# Dependencies and build artifacts
-dist/
+*.py[cod]
+*$py.class
+*.so
+.Python
 build/
-target/
-node_modules/
-.venv/
-venv/
-.env
-.env.local
-*.env.*
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
 
-# Logs and temporary files
-*.log
-*.tmp
-*.swp
-
-# Editor/IDE files
+# IDE
 .vscode/
 .idea/
 
-# Coverage reports
-coverage/
-htmlcov/
-.coverage
+# Environment
+.env
+.env.local
+.env.*
 
-# MyPy cache
-.mypy_cache/
+# Logs
+*.log
 
-# Pytest cache
-.pytest_cache/
+# OS
+.DS_Store
+Thumbs.db
 ```