离线同步完整实现

[robinv8]

Dashboard 显示待同步数量 banner 和"重试"按钮，但 DashboardViewModel.retrySync() 未实现。PendingShareStore 有读写 API，但主 App 未在启动时消费。需要完整实现离线同步逻辑。

Status

• Task Key: offline-sync
• Spec Revision: aaa5e6d9
• Approved Revision: aaa5e6d9
• Approval State: approved
• Current Stage: definition
• Next Stage: run
• Workflow Entry State: ready_to_start
• Attempt Count: 0
• Max Retry Count: 3
• Code Publication State: not_applicable
• Close On Done: auto
• Depends On: share-extension-image

Dependencies

• Depends on Share Extension 图片收集 #26

Acceptance Criteria

• Share Extension 离线发送后，主 App 启动自动同步
• 同步状态 UI 正确反映进度
• 网络恢复后能继续同步未完成的任务
• 支持手动触发重试（现有"重试"按钮）

Verification

• 断网状态通过 Share Extension 发送内容
• 打开主 App 观察自动同步
• 测试手动重试按钮
• 验证网络恢复后继续同步

Source

• Spec: docs/prd/ios-improvement.md
• Parent Issue: (no parent)

[robinv8]

Task published from spec docs/prd/ios-improvement.md at revision aaa5e6d9.

iron_tree:
  version: 1
  task_key: offline-sync
  issue_number: 28
  spec_revision: aaa5e6d9
  approved_revision: aaa5e6d9
  sequence: 1
  event: task_published
  current_stage: definition
  next_stage: run
  workflow_entry_state: ready_to_start
  approval_state: approved
  attempt_count: 0
  max_retry_count: 3
  code_publication_state: not_applicable
  pass_fail_outcome: null
  completion_basis: null
  code_ref: null