feat(ux): Sprint 3 mobile nav, sync conflicts, and resilience

Improve mobile bottom navigation, accessible dialogs and cards, explicit
sync conflict resolution, i18n error messages, encrypted draft autosave,
and persistent storage hints for offline data safety.

Co-authored-by: Cursor <cursoragent@cursor.com>

client/src/services/sync.ts

@@ -2,6 +2,11 @@ import { db, type SyncQueueItem } from './db.js'
 import { getActiveMasterKey } from './auth.js'
 import { apiFetch } from './api.js'
 import { getLogbookAccess } from './logbookAccess.js'
+import {
+  clearSyncConflict,
+  reportSyncConflict,
+  type SyncConflict
+} from './syncConflicts.js'
 
 const API_BASE = '/api/sync'
 const syncingLogbooks = new Set<string>()
@@ -177,10 +182,19 @@ async function pushChanges(logbookId: string): Promise<boolean> {
       const queueItem = pending[i]
       if (!queueItem) continue
 
-      if (res.status === 'success' || res.status === 'conflict') {
+      if (res.status === 'success') {
         if (queueItem.id !== undefined) {
           await db.syncQueue.delete(queueItem.id)
         }
+        clearSyncConflict(logbookId, res.payloadId ?? queueItem.payloadId, queueItem.type)
+      } else if (res.status === 'conflict') {
+        reportSyncConflict({
+          logbookId,
+          payloadId: res.payloadId ?? queueItem.payloadId,
+          type: queueItem.type,
+          reason: typeof res.reason === 'string' ? res.reason : 'Server version is newer',
+          queueItemId: queueItem.id
+        })
       } else {
         console.error(`Sync failed for item ${res.payloadId}:`, res.error)
       }
@@ -525,3 +539,43 @@ export function stopBackgroundSync() {
     syncIntervalId = null
   }
 }
+
+/** Accept server version: pull latest and drop the conflicting queue item. */
+export async function resolveSyncConflictUseServer(conflict: SyncConflict): Promise<void> {
+  if (conflict.queueItemId !== undefined) {
+    await db.syncQueue.delete(conflict.queueItemId)
+  } else {
+    const pending = await db.syncQueue
+      .where({ logbookId: conflict.logbookId })
+      .filter(
+        (item) => item.payloadId === conflict.payloadId && item.type === conflict.type
+      )
+      .toArray()
+    const ids = pending.map((p) => p.id).filter((id): id is number => id !== undefined)
+    if (ids.length > 0) await db.syncQueue.bulkDelete(ids)
+  }
+  clearSyncConflict(conflict.logbookId, conflict.payloadId, conflict.type)
+  await pullChanges(conflict.logbookId)
+}
+
+/** Keep local version: bump queue timestamp and retry push. */
+export async function resolveSyncConflictKeepLocal(conflict: SyncConflict): Promise<void> {
+  const bump = new Date(Date.now() + 1000).toISOString()
+  if (conflict.queueItemId !== undefined) {
+    await db.syncQueue.update(conflict.queueItemId, { updatedAt: bump })
+  } else {
+    const pending = await db.syncQueue
+      .where({ logbookId: conflict.logbookId })
+      .filter(
+        (item) => item.payloadId === conflict.payloadId && item.type === conflict.type
+      )
+      .toArray()
+    for (const item of pending) {
+      if (item.id !== undefined) {
+        await db.syncQueue.update(item.id, { updatedAt: bump })
+      }
+    }
+  }
+  clearSyncConflict(conflict.logbookId, conflict.payloadId, conflict.type)
+  await flushPushQueue(conflict.logbookId)
+}