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/features/uploads/preparer.dart

@@ -87,7 +87,9 @@ class UploadPreparer {
   /// 准备一张图片并入队。
   ///
   /// [sourcePath] 为 image_picker/camera 返回的源文件路径（App 沙箱内
-  /// 可直接 File 读取）；[filename] 缺省取源文件 basename。
+  /// 可直接 File 读取）；[filename] 缺省取源文件 basename；[force] 为
+  /// 查重弹窗「全部上传」的用户确认（Task 8）——落到任务行，由引擎在
+  /// initUpload 携带（仅 owner/admin 生效，服务端裁决）。
   ///
   /// 返回入队后的任务（state=queued）；失败返回 state=preparationFailed
   /// 的任务（不抛异常——准备失败是业务状态而非调用错误）。
@@ -97,6 +99,7 @@ class UploadPreparer {
     String? categoryId,
     required String sourcePath,
     String? filename,
+    bool force = false,
   }) {
     return _runBounded(
       () => _prepare(
@@ -105,6 +108,7 @@ class UploadPreparer {
         categoryId: categoryId,
         sourcePath: sourcePath,
         filename: filename,
+        force: force,
       ),
     );
   }
@@ -164,6 +168,7 @@ class UploadPreparer {
     required String? categoryId,
     required String sourcePath,
     required String? filename,
+    required bool force,
   }) async {
     final id = _newId();
     final clientTaskId = _newId();
@@ -188,6 +193,7 @@ class UploadPreparer {
         // 预检失败时占位（该行永不进入传输；成功路径 bytes 来自源 stat）。
         bytes: bytes > 0 ? bytes : 1,
         contentType: contentType ?? 'application/octet-stream',
+        force: force,
       ),
     );