feat(cover): 支持横版封面并收紧底栏图标间距

- Drama 新增 coverLandscape，WatchProgress 新增 dramaCoverLandscape
- 继续观看横幅优先使用横版封面，缺省回退竖版
- 底部导航栏图标与文字间距由 5dp 收紧至 1dp

test/watch/watch_records_controller_test.dart

@@ -8,6 +8,7 @@ import 'package:fruitshorts/core/data/models/feed_page.dart';
 import 'package:fruitshorts/core/data/models/home_feed.dart';
 import 'package:fruitshorts/core/data/models/page_result.dart';
 import 'package:fruitshorts/core/data/models/watch_progress.dart';
+import 'package:fruitshorts/core/data/models/watch_record.dart';
 import 'package:fruitshorts/core/data/repositories/catalog_repository.dart';
 import 'package:fruitshorts/core/data/repositories/watch_history_repository.dart';
 import 'package:fruitshorts/core/data/remote/api_client.dart';
@@ -278,6 +279,25 @@ void main() {
 
     expect(controller.error, '账号不存在，请先注册');
   });
+
+  test('should_prefer_page_landscape_cover_and_fall_back_to_portrait', () {
+    WatchRecord record(String? landscape) => WatchRecord(
+      progress: WatchProgress(
+        dramaId: '1',
+        episodeId: 'episode-1',
+        position: const Duration(seconds: 12),
+        duration: const Duration(seconds: 60),
+        dramaCover: '/files/poster.webp',
+        dramaCoverLandscape: landscape,
+      ),
+    );
+
+    expect(
+      record('/files/wide.webp').displayLandscapeCover,
+      '/files/wide.webp',
+    );
+    expect(record(null).displayLandscapeCover, '/files/poster.webp');
+  });
 }
 
 class ControlledWatchHistory implements WatchHistoryRepository {