Initial commit: Media server and Home Assistant integration

- FastAPI server for Windows media control via WinRT/SMTC
- Home Assistant custom integration with media player entity
- Script button entities for system commands
- Position tracking with grace period for track skip handling
- Server availability detection in HA entity

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

media_server/routes/health.py

@@ -0,0 +1,22 @@
+"""Health check endpoint."""
+
+import platform
+from typing import Any
+
+from fastapi import APIRouter
+
+router = APIRouter(prefix="/api", tags=["health"])
+
+
+@router.get("/health")
+async def health_check() -> dict[str, Any]:
+    """Health check endpoint - no authentication required.
+
+    Returns:
+        Health status and server information
+    """
+    return {
+        "status": "healthy",
+        "platform": platform.system(),
+        "version": "1.0.0",
+    }