fix: Windows event loop compatibility, EMQX API response handling, and test fix

- Add WindowsSelectorEventLoopPolicy for paho-mqtt on Windows
- Handle EMQX /status plain text and /metrics list responses
- Fix test_default_settings to ignore .env file
- Add __main__.py for python -m mqtt_home support

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

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

tests/test_config.py

@@ -3,7 +3,7 @@ from mqtt_home.config import Settings
 
 
 def test_default_settings():
-    s = Settings()
+    s = Settings(_env_file=None)
     assert s.mqtt_host == "localhost"
     assert s.mqtt_port == 1883
     assert s.web_port == 8000