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>

src/mqtt_home/main.py

@@ -1,7 +1,12 @@
 import asyncio
 import logging
+import sys
 from contextlib import asynccontextmanager
 
+# Windows compatibility: use SelectorEventLoop for paho-mqtt (add_reader/add_writer)
+if sys.platform == "win32":
+    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
+
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware