feat(app): P0 batch 2+2.5 — local upload dedup with batch dialog, album switch check, file size guard

P0-1 层 1 本地查重：
  - checkDuplicates：同账号+同相册+state=completed+filename+bytes 匹配
  - EnqueueResult 返回 enqueued+duplicates+skipped
  - capture_page + album_detail_page：批量单次弹窗（非逐张）三选一
    [跳过重复上传非重复] [全部上传] [取消]

P0-8 相册上传开关预检：album_detail_page 入队前检查 uploadEnabled，
  关闭时提示「该相册已关闭上传」+ 不入队

P1-8 文件大小预检：preparer 限单文件 ≤100MB（磁盘满由 on Object 兜底）

P0-7 更正：上传并发限制已有（kMaxParallelUploads=2），v2 分析误报

397/397 全绿、analyze 0

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

apps/mobile/lib/pages/capture_page.dart

@@ -285,7 +285,7 @@ class _CapturePageState extends ConsumerState<CapturePage>
             sourcePaths: [photo.path],
           );
           // 入队成功：短暂反馈（轻触 + 200ms 浮层），不逐张弹确认（§4.5）。
-          if (enqueued > 0 && mounted) _flashEnqueued();
+          if (enqueued.enqueued > 0 && mounted) _flashEnqueued();
         })
         .catchError((Object _) {
           // 单张失败吞掉（连拍不中断；失败任务/错误在徽章与队列页可见）。
@@ -308,19 +308,93 @@ class _CapturePageState extends ConsumerState<CapturePage>
     if (paths.isEmpty || !mounted) return;
     final l10n = AppLocalizations.of(context);
     final messenger = ScaffoldMessenger.of(context);
-    final count = await enqueueForUpload(
+
+    // P0-1 层 1：入队前查重（同相册已完成的 filename+bytes 匹配）。
+    final duplicates = await checkDuplicates(
+      ref,
+      accountId: widget.target.accountId,
+      albumId: widget.target.albumId,
+      sourcePaths: paths,
+    );
+
+    Set<String> skipPaths;
+    if (duplicates != null && duplicates.isNotEmpty && mounted) {
+      // 批量确认弹窗（单次，非逐张）。
+      final skip = await _showDuplicateDialog(l10n, duplicates, paths);
+      if (skip == null) return; // 取消——不上传。
+      skipPaths = skip;
+    } else {
+      skipPaths = <String>{};
+    }
+
+    final result = await enqueueForUpload(
       ref,
       accountId: widget.target.accountId,
       albumId: widget.target.albumId,
       categoryId: _categoryId,
       sourcePaths: paths,
+      skipPaths: skipPaths.toList(),
     );
     if (!mounted) return;
+    final uploaded = result.enqueued;
+    final skipped = result.skipped;
     messenger.showSnackBar(
-      SnackBar(content: Text(l10n.uploadEnqueuedCount(count))),
+      SnackBar(
+        content: Text(
+          skipped > 0
+              ? '$uploaded 张已入队，$skipped 张重复已跳过'
+              : l10n.uploadEnqueuedCount(uploaded),
+        ),
+      ),
     );
   }
 
+  /// 批量重复确认弹窗：返回 null=取消 / 空 Set=全部上传 / 非空=跳过项路径集。
+  Future<Set<String>?> _showDuplicateDialog(
+    AppLocalizations l10n,
+    List<DuplicateMatch> duplicates,
+    List<String> allPaths,
+  ) async {
+    // 找出与 duplicates 匹配的路径（filename 一致即视为重复项）。
+    final dupFilenames = duplicates.map((d) => d.filename).toSet();
+    final dupPaths = allPaths
+        .where((p) => dupFilenames.contains(p.split('/').last))
+        .toSet();
+    final nonDupCount = allPaths.length - dupPaths.length;
+
+    final choice = await showDialog<String>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('可能已上传过'),
+        content: Text(
+          '${duplicates.length} 张照片可能已上传到该相册'
+          '${nonDupCount > 0 ? '（另 $nonDupCount 张不重复）' : ''}\n\n'
+          '${duplicates.take(3).map((d) => d.filename).join('、')}'
+          '${duplicates.length > 3 ? ' …' : ''}',
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.of(ctx).pop('cancel'),
+            child: const Text('取消'),
+          ),
+          if (nonDupCount > 0)
+            TextButton(
+              onPressed: () => Navigator.of(ctx).pop('skip'),
+              child: Text('跳过重复，上传 $nonDupCount 张'),
+            ),
+          FilledButton(
+            onPressed: () => Navigator.of(ctx).pop('all'),
+            child: Text('全部上传 ${allPaths.length} 张'),
+          ),
+        ],
+      ),
+    );
+
+    if (choice == 'cancel' || choice == null) return null;
+    if (choice == 'skip') return dupPaths;
+    return <String>{}; // 'all' = 不跳过任何
+  }
+
   void _switchCategory(String? categoryId) {
     if (categoryId == _categoryId) return;
     setState(() => _categoryId = categoryId);