feat(notifications): deep-link bell rows to source stack and container logs (#692)

Add stack_name and container_name columns to notification_history so bell
rows can act as jump points. Producers (AutoHeal, Docker events) pass the
container context through dispatchAlert; the panel renders routable rows
as buttons that load the target stack and, when a container name is
present, open its logs modal. Non-structural notifications stay as
passive display rows.

backend/src/services/NotificationService.ts

@@ -39,12 +39,19 @@ export class NotificationService {
      *  - agents table (all tiers): global fallback channels used when no
      *    notification_routes match or when no stackName is provided.
      */
-    public async dispatchAlert(level: 'info' | 'warning' | 'error', message: string, stackName?: string) {
+    public async dispatchAlert(
+        level: 'info' | 'warning' | 'error',
+        message: string,
+        stackName?: string,
+        containerName?: string,
+    ) {
         // 1. Log to history and get the full inserted record (with id)
         const notification = this.dbService.addNotificationHistory({
             level,
             message,
-            timestamp: Date.now()
+            timestamp: Date.now(),
+            stack_name: stackName,
+            container_name: containerName,
         });
 
         // 2. Push to connected browser clients via WebSocket