feat(app): wire server dedup - force passthrough + PHOTO_DUPLICATE classification & l10n

Task 8: close the gap between server-side duplicate detection (90dcc58)
and the app.

- ApiClient.mapDioException: normalize 409 wire body reusing
  VALIDATION_FAILED with message=PHOTO_DUPLICATE to
  ErrorCodes.photoDuplicate (message-based; auto-compat if the contract
  later adds a dedicated code)
- l10n zh/en errorPhotoDuplicate; error_l10n maps the code (queue page
  inherits via fallback)
- UploadEngine._classifyFailure: PHOTO_DUPLICATE joins the no-auto-retry
  bucket (retrying the same init body would 409 again); force to skip
  dedup travels only through the enqueue path
- UploadTasks drift table +force column (schema v2, addColumn migration;
  legacy rows default false); UploadTaskDraft/UploadTask/prepare carry it
- enqueueForUpload +forcePaths; duplicate dialog "全部上传" (capture page
  + album detail page) now returns DuplicateDialogChoice so confirmed
  duplicates enqueue with force=true (server adjudicates owner/admin)
- engine init body carries force only when true (absent otherwise)

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

apps/mobile/lib/core/api_client.dart

@@ -137,6 +137,18 @@ class ApiClient {
         final Object? message = data['message'];
         final Object? requestId = data['requestId'];
         if (code is String && message is String) {
+          // P0-1 服务端查重拒绝（Task 8）：409 的 wire code 复用
+          // VALIDATION_FAILED，按 message=PHOTO_DUPLICATE 识别归一——所有
+          // 调用方（上传引擎分类/l10n 文案）据此走查重分支；契约日后若设
+          // 独立 code，此处识别与透传均兼容。
+          if (status == 409 && message.contains(ErrorCodes.photoDuplicate)) {
+            return AppException(
+              code: ErrorCodes.photoDuplicate,
+              message: message,
+              requestId: requestId is String ? requestId : null,
+              statusCode: status,
+            );
+          }
           return AppException(
             code: code,
             message: message,

apps/mobile/lib/core/error_codes.dart

@@ -68,6 +68,12 @@ abstract final class ErrorCodes {
 
   // ── 以下为客户端本地伪码（契约外，见类注释） ──
 
+  /// 照片疑似重复（409，服务端查重拒绝）。P0-1 契约现状：wire 体 code
+  /// 复用 VALIDATION_FAILED、靠 message=PHOTO_DUPLICATE 识别——ApiClient
+  /// 归一为本码（若契约日后设独立 code，归一自动兼容）。skip 服务端查重
+  /// 的 force 请求仅 owner/admin 生效（服务端裁决）。
+  static const String photoDuplicate = 'PHOTO_DUPLICATE';
+
   /// 网络连接失败（DNS/握手/断网等连接层错误）。
   static const String networkError = 'NETWORK_ERROR';
 

apps/mobile/lib/core/error_l10n.dart

@@ -26,6 +26,8 @@ extension AppLocalizationsErrorX on AppLocalizations {
         return errorAuthTokenExpired;
       case ErrorCodes.validationFailed:
         return errorValidation;
+      case ErrorCodes.photoDuplicate: // P0-1 服务端查重拒绝（409 归一码）。
+        return errorPhotoDuplicate;
       case ErrorCodes.networkError:
         return errorNetwork;
       case ErrorCodes.networkTimeout: