Add manual ping/health check button to device cards

Adds a refresh icon button on each device card that triggers an immediate
health check via POST /devices/{id}/ping, showing online status with
latency or offline result as a toast notification.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/core/processing/processor_manager.py

@@ -1080,6 +1080,13 @@ class ProcessorManager:
             except Exception as e:
                 logger.error(f"Failed to sync LED count for {device_id}: {e}")
 
+    async def force_device_health_check(self, device_id: str) -> dict:
+        """Run an immediate health check for a device and return the result."""
+        if device_id not in self._devices:
+            raise ValueError(f"Device {device_id} not found")
+        await self._check_device_health(device_id)
+        return self.get_device_health_dict(device_id)
+
     # ===== HELPERS =====
 
     def has_device(self, device_id: str) -> bool: