feat(sprint-6): Phase 6 — Notifications (WebSocket) + PWA

- WebSocket: Spring STOMP + SockJS, NotificationService, persistent notifications table
- NotificationController: GET/PUT endpoints for notification management
- Frontend: notification bell with unread badge, dropdown panel, real-time via STOMP
- PWA: manifest.json, service worker (manual sw.js), offline page, install prompt
- PWA icons (192+512), dark theme colors, standalone display
- Full i18n (de/en) for notifications and PWA
- Flyway V10 migration for notifications table
- spring-boot-starter-websocket dependency added

cannamanage-frontend/src/__tests__/services/distributions.test.tsx

@@ -1,16 +1,15 @@
-import { renderHook, waitFor } from "@testing-library/react"
-import { afterAll, afterEach, beforeAll, describe, expect, it } from "vitest"
-import { QueryClient, QueryClientProvider } from "@tanstack/react-query"
 import React from "react"
-
 import {
+  useCreateDistributionMutation,
   useDistributionsQuery,
   useQuotaQuery,
-  useCreateDistributionMutation,
 } from "@/services/distributions"
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query"
+import { renderHook, waitFor } from "@testing-library/react"
+import { afterAll, afterEach, beforeAll, describe, expect, it } from "vitest"
 
-import { server } from "../mocks/server"
 import { mockDistributionsPage, mockQuotaStatus } from "../mocks/handlers"
+import { server } from "../mocks/server"
 
 beforeAll(() => server.listen({ onUnhandledRequest: "error" }))
 afterEach(() => server.resetHandlers())