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/store/slices/todoSlice.ts

@@ -1,4 +1,4 @@
-import { todoApi } from '../../api/client'
+import { todoRepo } from '../../repo/todoRepo'
 import type { StoreApi } from 'zustand'
 import type { TripStoreState } from '../tripStore'
 import type { TodoItem } from '../../types'
@@ -17,7 +17,7 @@ export interface TodoSlice {
 export const createTodoSlice = (set: SetState, get: GetState): TodoSlice => ({
   addTodoItem: async (tripId, data) => {
     try {
-      const result = await todoApi.create(tripId, data)
+      const result = await todoRepo.create(tripId, data as Record<string, unknown>)
       set(state => ({ todoItems: [...state.todoItems, result.item] }))
       return result.item
     } catch (err: unknown) {
@@ -27,7 +27,7 @@ export const createTodoSlice = (set: SetState, get: GetState): TodoSlice => ({
 
   updateTodoItem: async (tripId, id, data) => {
     try {
-      const result = await todoApi.update(tripId, id, data)
+      const result = await todoRepo.update(tripId, id, data as Record<string, unknown>)
       set(state => ({
         todoItems: state.todoItems.map(item => item.id === id ? result.item : item)
       }))
@@ -41,7 +41,7 @@ export const createTodoSlice = (set: SetState, get: GetState): TodoSlice => ({
     const prev = get().todoItems
     set(state => ({ todoItems: state.todoItems.filter(item => item.id !== id) }))
     try {
-      await todoApi.delete(tripId, id)
+      await todoRepo.delete(tripId, id)
     } catch (err: unknown) {
       set({ todoItems: prev })
       throw new Error(getApiErrorMessage(err, 'Error deleting todo'))
@@ -55,7 +55,7 @@ export const createTodoSlice = (set: SetState, get: GetState): TodoSlice => ({
       )
     }))
     try {
-      await todoApi.update(tripId, id, { checked })
+      await todoRepo.update(tripId, id, { checked })
     } catch {
       set(state => ({
         todoItems: state.todoItems.map(item =>