feat(cache): add cache health monitoring and validation system, see #730

- Add cache entry validator service for data integrity checks
- Add cache health monitor service for periodic health checks
- Enhance model cache and scanner with validation support
- Update websocket manager for health status broadcasting
- Add initialization banner service for cache health alerts
- Add comprehensive test coverage for new services
- Update translations across all locales
- Refactor sync translation keys script

py/services/websocket_manager.py

@@ -255,6 +255,42 @@ class WebSocketManager:
             self._download_progress.pop(download_id, None)
             logger.debug(f"Cleaned up old download progress for {download_id}")
             
+    async def broadcast_cache_health_warning(self, report: 'HealthReport', page_type: str = None):
+        """
+        Broadcast cache health warning to frontend.
+
+        Args:
+            report: HealthReport instance from CacheHealthMonitor
+            page_type: The page type (loras, checkpoints, embeddings)
+        """
+        from .cache_health_monitor import CacheHealthStatus
+
+        # Only broadcast if there are issues
+        if report.status == CacheHealthStatus.HEALTHY:
+            return
+
+        payload = {
+            'type': 'cache_health_warning',
+            'status': report.status.value,
+            'message': report.message,
+            'pageType': page_type,
+            'details': {
+                'total': report.total_entries,
+                'valid': report.valid_entries,
+                'invalid': report.invalid_entries,
+                'repaired': report.repaired_entries,
+                'corruption_rate': f"{report.corruption_rate:.1%}",
+                'invalid_paths': report.invalid_paths[:5],  # Limit to first 5
+            }
+        }
+
+        logger.info(
+            f"Broadcasting cache health warning: {report.status.value} "
+            f"({report.invalid_entries} invalid entries)"
+        )
+
+        await self.broadcast(payload)
+
     def get_connected_clients_count(self) -> int:
         """Get number of connected clients"""
         return len(self._websockets)