Wrap sensor history imports in try/except, add logging to all failure points

src/data/data_providers.py

@@ -332,9 +332,13 @@ class VineSensorService(BaseService):
         hours_back: int = 24,
     ) -> Dict[str, Any]:
         """Hourly averages for a device group over the last N hours."""
-        from src.thingsboard_client import (
-            AIR_KEYS, CROP_KEYS, SOIL_KEYS, DEVICE_REGISTRY, VineArea,
-        )
+        try:
+            from src.thingsboard_client import (
+                AIR_KEYS, CROP_KEYS, SOIL_KEYS, DEVICE_REGISTRY, VineArea,
+            )
+        except Exception as exc:
+            log.error("ThingsBoard client import failed: %s", exc)
+            return {"error": f"ThingsBoard client unavailable: {exc}"}
 
         key_map = {"air": AIR_KEYS, "crop": CROP_KEYS, "soil": SOIL_KEYS}
         keys = key_map.get(device_type.lower())
@@ -373,6 +377,7 @@ class VineSensorService(BaseService):
             hourly = merged.resample("1h").mean(numeric_only=True)
             return summarise_dataframe(hourly)
         except Exception as exc:
+            log.error("Sensor history query failed: %s", exc)
             return {"error": f"Sensor history failed: {exc}"}