Update backend/api/routes/health.py: circuit breaker, weather fix, TB health fix

backend/api/routes/health.py

@@ -13,14 +13,14 @@ router = APIRouter()
 
 
 async def _check_thingsboard() -> bool:
-    """Check ThingsBoard connectivity without blocking the event loop."""
+    """Check ThingsBoard connectivity by hitting the login page."""
     tb_host = os.environ.get("THINGSBOARD_HOST", "")
     if not tb_host:
         return False
     try:
         import urllib.request
-        url = f"{tb_host.rstrip('/')}/api/noauth/health"
-        # Run sync urllib in thread pool to avoid blocking event loop
+        # Use root URL — TB always responds to GET / with 200 (login page)
+        url = tb_host.rstrip("/") + "/"
         loop = asyncio.get_event_loop()
         resp = await loop.run_in_executor(
             None, lambda: urllib.request.urlopen(url, timeout=3)