feat(app): 选图拦截 v2——硬封锁+仅本机判定，治点选卡顿与连点强穿

问题（用户反馈）：v1 服务器单项预检（2s 帽）弱网下把每次点选的勾选卡
0.5~2s（selectPredicate await 期间 selectAsset 不执行）；配合「二次点击
强制选择」活口，重复照片被连点强制选中，拦截形同虚设。

- 判定仅查本机 TaskStore（毫秒级）——服务器查重退至入队统一弹窗+409 兜底
- 硬封锁：本机命中每次点击均拒选（_forced 放行集移除），文案不再引导再点
- 判定缓存升级 in-flight Future 共享（putIfAbsent）：同一照片连点只判一次
  （清偿 9-29 评审登记 Minor 遗留）
- 构造去 client/serverCheckTimeout；iOS title 空放行（跨设备判定在入队弹窗）
- 已接受限制（用户拍板 A）：后台已删照片重传同文件被本机历史永拦

Co-Authored-By: Claude Code <noreply@anthropic.com>

apps/mobile/lib/l10n/app_en.arb

@@ -351,7 +351,7 @@
     }
   },
   "uploadPickNone": "No photos selected",
-  "pickerDuplicateBlocked": "Already uploaded to this album — tap again to select anyway",
+  "pickerDuplicateBlocked": "This photo has already been uploaded to this album",
   "albumManagePhotos": "Manage photos",
   "albumTakeFirstPhoto": "Take the first photo",
   "albumUploadDisabledHint": "Uploads are off for this album. New photos cannot be added right now",