feat: complete offline write support with mutation queue + runtime SW cache config

- Add offline CRUD to todoRepo, budgetRepo, reservationRepo, accommodationRepo,
  dayRepo, tripRepo, fileRepo with optimistic Dexie writes and mutation queue
- Wire all store slices (todo, budget, reservations, files, dayNotes, assignments,
  tripStore) through repos for offline-aware writes
- Cover archive/unarchive, file toggleStar/update/delete, assignment create/delete,
  day title/notes update offline paths
- Migrate service worker from generateSW to injectManifest (custom sw.ts) with
  runtime-configurable api-data (7d/500) and map-tiles (30d/1000) cache policies
- Add Settings → Offline cache configuration UI with save/reset and live SW postMessage
- Extend mutationQueue flush to cover all writable Dexie tables

client/src/sw.ts

@@ -0,0 +1,128 @@
+/// <reference lib="webworker" />
+
+import { clientsClaim } from 'workbox-core';
+import {
+  precacheAndRoute,
+  cleanupOutdatedCaches,
+  createHandlerBoundToURL,
+} from 'workbox-precaching';
+import { registerRoute, NavigationRoute } from 'workbox-routing';
+import { NetworkFirst, CacheFirst } from 'workbox-strategies';
+import { ExpirationPlugin } from 'workbox-expiration';
+import { CacheableResponsePlugin } from 'workbox-cacheable-response';
+import {
+  DEFAULT_SW_CONFIG,
+  readSwConfigFromIDB,
+  validateSwConfig,
+  type SwCacheConfig,
+} from './sync/swConfig';
+
+declare const self: ServiceWorkerGlobalScope;
+
+self.skipWaiting();
+clientsClaim();
+
+// Inject precache manifest (replaced by vite-plugin-pwa at build time)
+// @ts-expect-error __WB_MANIFEST is injected at build time
+precacheAndRoute(self.__WB_MANIFEST);
+cleanupOutdatedCaches();
+
+// ── Static routes (not user-configurable) ─────────────────────────────────────
+
+registerRoute(
+  new NavigationRoute(createHandlerBoundToURL('index.html'), {
+    denylist: [/^\/api/, /^\/uploads/, /^\/mcp/],
+  }),
+);
+
+registerRoute(
+  /^https:\/\/unpkg\.com\/.*/i,
+  new CacheFirst({
+    cacheName: 'cdn-libs',
+    plugins: [
+      new ExpirationPlugin({ maxEntries: 30, maxAgeSeconds: 365 * 24 * 60 * 60 }),
+      new CacheableResponsePlugin({ statuses: [0, 200] }),
+    ],
+  }),
+  'GET',
+);
+
+registerRoute(
+  /\/uploads\/(?:covers|avatars)\/.*/i,
+  new CacheFirst({
+    cacheName: 'user-uploads',
+    plugins: [
+      new ExpirationPlugin({ maxEntries: 300, maxAgeSeconds: 7 * 24 * 60 * 60 }),
+      new CacheableResponsePlugin({ statuses: [200] }),
+    ],
+  }),
+  'GET',
+);
+
+// ── Configurable routes ────────────────────────────────────────────────────────
+// Routes are registered once. Strategy instances are replaced on config change
+// so the stable handler wrapper always delegates to the current instance.
+
+const DAY = 24 * 60 * 60;
+
+function buildApiStrategy(cfg: SwCacheConfig): NetworkFirst {
+  return new NetworkFirst({
+    cacheName: 'api-data',
+    networkTimeoutSeconds: 5,
+    plugins: [
+      new ExpirationPlugin({
+        maxEntries: cfg.apiMaxEntries,
+        maxAgeSeconds: cfg.apiTtlDays * DAY,
+      }),
+      new CacheableResponsePlugin({ statuses: [200] }),
+    ],
+  });
+}
+
+function buildTilesStrategy(cfg: SwCacheConfig): CacheFirst {
+  return new CacheFirst({
+    cacheName: 'map-tiles',
+    plugins: [
+      new ExpirationPlugin({
+        maxEntries: cfg.tilesMaxEntries,
+        maxAgeSeconds: cfg.tilesTtlDays * DAY,
+      }),
+      new CacheableResponsePlugin({ statuses: [0, 200] }),
+    ],
+  });
+}
+
+let apiStrategy = buildApiStrategy(DEFAULT_SW_CONFIG);
+let cartoStrategy = buildTilesStrategy(DEFAULT_SW_CONFIG);
+let osmStrategy = buildTilesStrategy(DEFAULT_SW_CONFIG);
+
+function applyConfig(cfg: SwCacheConfig): void {
+  apiStrategy    = buildApiStrategy(cfg);
+  cartoStrategy  = buildTilesStrategy(cfg);
+  osmStrategy    = buildTilesStrategy(cfg);
+}
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+registerRoute(/\/api\/(?!auth|admin|backup|settings).*/i,  { handle: (o: any) => apiStrategy.handle(o) },   'GET');
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+registerRoute(/^https:\/\/[a-d]\.basemaps\.cartocdn\.com\/.*/i, { handle: (o: any) => cartoStrategy.handle(o) }, 'GET');
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+registerRoute(/^https:\/\/[a-c]\.tile\.openstreetmap\.org\/.*/i, { handle: (o: any) => osmStrategy.handle(o) },  'GET');
+
+// Load persisted config asynchronously; replaces defaults if user has saved settings
+readSwConfigFromIDB()
+  .then(cfg => { if (cfg) applyConfig(cfg); })
+  .catch(() => {});
+
+// ── Message handler ────────────────────────────────────────────────────────────
+
+self.addEventListener('message', (event: ExtendableMessageEvent) => {
+  const data = event.data as { type?: string; config?: unknown };
+  if (data?.type !== 'UPDATE_CACHE_CONFIG' || !data.config) return;
+
+  const validated = validateSwConfig(data.config as Partial<SwCacheConfig>);
+  applyConfig(validated);
+
+  // Acknowledge back to the sending client
+  (event.source as WindowClient | null)?.postMessage({ type: 'CACHE_CONFIG_APPLIED' });
+});