新增：首页 Feed 接入真实数据——四态/尾部三态/聚合曝光埋点，社区 demo 消亡第一页（T3-14）

- home_page Feed segment 改接 CommunityController：骨架屏首载、空态 CTA、
  错误横幅重试、下拉刷新（失败保留旧列表 + SnackBar）、触底游标翻页
  （失败态只走显式重试，不随滚动风暴自动重打）
- PostCard 三形态（单图通栏 4:3 / 多图折叠封面 +N 角标 / 纯文字 6 行）+
  PostMediaGrid（列数规则 + ink 80% scrim 精算）+ LikeButton（error 族修订
  Colors.red，T3-14 纯展示禁用态，ToggleSync 接线留 T3-15/16）+ FeedSkeleton
  （呼吸动效尊重减弱动态设置）；降级作者统一「宠友」占位
- SignedNetworkImage：预签名 URL 缓存 key 剥离 X-Amz-* 签名参数，
  RemoteImage 全仓换用（同图不同签名命中同一缓存条目）
- feed 域埋点：feed_viewed 聚合曝光（浏览段开/结算于切 Tab、切分段、
  退后台、销毁；≥50% 可见 ≥500ms 段内按帖去重，postId 不上报）+
  feed_load_failed（refresh/load_more 双路，会话失效不报）
- integration_test/feed_live_test.dart：compose 六容器 Linux 桌面真链路
  实测入口（PATBOND_FEED_LIVE=1 门控，默认跳过）
- 测试 379 → 421（+42）：四态/尾部三态/翻页不丢不重/降级作者/曝光结算
  时机/缓存 key/事件属性全覆盖；analyze 0，format 无 diff

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

test/core/network/signed_network_image_test.dart

@@ -0,0 +1,70 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:patbond_flutter/core/network/signed_network_image.dart';
+
+void main() {
+  group('presignedImageCacheKey', () {
+    test('剥离全部 X-Amz-* 签名参数（大小写不敏感）', () {
+      const url =
+          'http://127.0.0.1:9000/patbond-media/post_image/a-1.jpg'
+          '?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=cred'
+          '&X-Amz-Date=20260909T000000Z&X-Amz-Expires=3600'
+          '&X-Amz-SignedHeaders=host&x-amz-signature=deadbeef';
+      expect(
+        presignedImageCacheKey(url),
+        'http://127.0.0.1:9000/patbond-media/post_image/a-1.jpg',
+      );
+    });
+
+    test('保留非签名 query 参数', () {
+      const url = 'https://cdn.example.com/p.jpg?w=300&X-Amz-Signature=sig';
+      expect(
+        presignedImageCacheKey(url),
+        'https://cdn.example.com/p.jpg?w=300',
+      );
+    });
+
+    test('无签名参数原样返回', () {
+      expect(
+        presignedImageCacheKey('https://cdn.example.com/p.jpg?w=300&q=80'),
+        'https://cdn.example.com/p.jpg?w=300&q=80',
+      );
+      expect(
+        presignedImageCacheKey('https://cdn.example.com/p.jpg'),
+        'https://cdn.example.com/p.jpg',
+      );
+    });
+
+    test('非法 URL 不炸，退回原串', () {
+      expect(presignedImageCacheKey('::not a url::'), '::not a url::');
+    });
+  });
+
+  group('SignedNetworkImage', () {
+    test('同对象不同签名 → 判等（命中同一 ImageCache 条目）', () {
+      final first = SignedNetworkImage(
+        'http://127.0.0.1:9000/m/a.jpg?X-Amz-Signature=sig1&X-Amz-Date=d1',
+      );
+      final second = SignedNetworkImage(
+        'http://127.0.0.1:9000/m/a.jpg?X-Amz-Signature=sig2&X-Amz-Date=d2',
+      );
+      expect(first, second);
+      expect(first.hashCode, second.hashCode);
+    });
+
+    test('不同对象 → 不判等', () {
+      final first = SignedNetworkImage(
+        'http://127.0.0.1:9000/m/a.jpg?X-Amz-Signature=sig',
+      );
+      final second = SignedNetworkImage(
+        'http://127.0.0.1:9000/m/b.jpg?X-Amz-Signature=sig',
+      );
+      expect(first, isNot(second));
+    });
+
+    test('scale 参与判等', () {
+      final first = SignedNetworkImage('http://h/m/a.jpg');
+      final second = SignedNetworkImage('http://h/m/a.jpg', scale: 2);
+      expect(first, isNot(second));
+    });
+  });
+}

test/core/widgets/post_card_test.dart

@@ -0,0 +1,102 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:patbond_flutter/core/theme/app_theme.dart';
+import 'package:patbond_flutter/core/widgets/like_button.dart';
+import 'package:patbond_flutter/core/widgets/post_card.dart';
+import 'package:patbond_flutter/core/widgets/post_media_grid.dart';
+import 'package:patbond_flutter/features/community/community_models.dart';
+import 'package:patbond_flutter/widgets/common.dart';
+
+import '../../helpers/community_test_helpers.dart';
+
+FeedCard cardFrom(Map<String, dynamic> overrides) =>
+    FeedCard.fromJson({...sampleFeedCardJson(), ...overrides});
+
+Widget wrap(Widget child) => MaterialApp(
+  theme: buildAppTheme(),
+  home: Scaffold(body: SingleChildScrollView(child: child)),
+);
+
+void main() {
+  testWidgets('单图形态：通栏 4:3 出血，不走九宫格，预览 2 行', (tester) async {
+    final card = cardFrom({'mediaCount': 1});
+    await tester.pumpWidget(wrap(PostCard(card: card)));
+
+    expect(find.byType(AspectRatio), findsOneWidget);
+    expect(find.byType(PostMediaGrid), findsNothing);
+    final preview = tester.widget<Text>(find.text('晒了一下午太阳。'));
+    expect(preview.maxLines, 2);
+  });
+
+  testWidgets('多图形态：九宫格折叠封面 + 「+N」角标（契约只带封面与计数）', (tester) async {
+    final card = cardFrom({'mediaCount': 5});
+    await tester.pumpWidget(wrap(PostCard(card: card)));
+
+    expect(find.byType(PostMediaGrid), findsOneWidget);
+    expect(find.text('+4'), findsOneWidget);
+  });
+
+  testWidgets('纯文字形态：无媒体区，正文放宽 6 行、15/1.6', (tester) async {
+    final card = cardFrom({'coverImage': null, 'mediaCount': 0});
+    await tester.pumpWidget(wrap(PostCard(card: card)));
+
+    expect(find.byType(PostMediaGrid), findsNothing);
+    expect(find.byType(AspectRatio), findsNothing);
+    final preview = tester.widget<Text>(find.text('晒了一下午太阳。'));
+    expect(preview.maxLines, 6);
+    expect(preview.style?.fontSize, 15);
+  });
+
+  testWidgets('头部行：作者名 + 相对时间；求助帖追加 accent 标', (tester) async {
+    final card = cardFrom({
+      'category': 'help',
+      'publishedAt': DateTime.now()
+          .subtract(const Duration(hours: 2))
+          .toUtc()
+          .toIso8601String(),
+    });
+    await tester.pumpWidget(wrap(PostCard(card: card)));
+
+    expect(find.text('毛毛的铲屎官'), findsOneWidget);
+    expect(find.text('2 小时前'), findsOneWidget);
+    expect(find.widgetWithText(TagPill, '求助'), findsOneWidget);
+  });
+
+  testWidgets('降级作者：占位头像 + 「宠友」默认名', (tester) async {
+    final card = cardFrom({
+      'author': sampleAuthorJson(nickname: null, avatarUrl: null),
+    });
+    await tester.pumpWidget(wrap(PostCard(card: card)));
+
+    expect(find.text('宠友'), findsOneWidget);
+    expect(find.text('毛毛的铲屎官'), findsNothing);
+  });
+
+  testWidgets('操作行：计数与激活态展示；T3-14 纯展示点按无副作用', (tester) async {
+    final card = cardFrom({
+      'likedByMe': true,
+      'likeCount': 6,
+      'bookmarkedByMe': false,
+      'bookmarkCount': 2,
+      'commentCount': 3,
+    });
+    await tester.pumpWidget(wrap(PostCard(card: card)));
+
+    expect(find.text('6'), findsOneWidget);
+    expect(find.text('2'), findsOneWidget);
+    expect(find.text('3'), findsOneWidget);
+    // 点赞激活：实心 favorite + error 色（Colors.red 修订 D6）。
+    final likeIcon = tester.widget<Icon>(find.byIcon(Icons.favorite));
+    expect(likeIcon.color, AppColors.error);
+    // 收藏未激活：描边 + inkSoft。
+    final bookmarkIcon = tester.widget<Icon>(
+      find.byIcon(Icons.bookmark_border),
+    );
+    expect(bookmarkIcon.color, AppColors.inkSoft);
+
+    // 回调未接（null）：点按不抛错、无状态变化。
+    await tester.tap(find.byType(LikeButton).first, warnIfMissed: false);
+    await tester.pump();
+    expect(find.byIcon(Icons.favorite), findsOneWidget);
+  });
+}

test/core/widgets/post_media_grid_test.dart

@@ -0,0 +1,100 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:patbond_flutter/core/theme/app_theme.dart';
+import 'package:patbond_flutter/core/widgets/feed_skeleton.dart';
+import 'package:patbond_flutter/core/widgets/post_media_grid.dart';
+import 'package:patbond_flutter/widgets/common.dart';
+
+Widget wrap(Widget child, {bool disableAnimations = false}) => MaterialApp(
+  theme: buildAppTheme(),
+  home: MediaQuery(
+    data: MediaQueryData(disableAnimations: disableAnimations),
+    child: Scaffold(body: SingleChildScrollView(child: child)),
+  ),
+);
+
+List<String> urls(int count) => List.generate(
+  count,
+  (i) => 'https://minio.local/p$i.jpg?X-Amz-Signature=s',
+);
+
+void main() {
+  group('PostMediaGrid 列数规则（05 §3.2）', () {
+    test('2、4 图 → 2 列；3、5–9 图 → 3 列', () {
+      expect(PostMediaGrid.columnsFor(2), 2);
+      expect(PostMediaGrid.columnsFor(4), 2);
+      expect(PostMediaGrid.columnsFor(3), 3);
+      for (var n = 5; n <= 9; n++) {
+        expect(PostMediaGrid.columnsFor(n), 3);
+      }
+    });
+
+    testWidgets('4 图渲染 4 格网格', (tester) async {
+      await tester.pumpWidget(wrap(PostMediaGrid(urls: urls(4))));
+      expect(find.byType(RemoteImage), findsNWidgets(4));
+      expect(find.byType(GridView), findsOneWidget);
+    });
+
+    testWidgets('超 9 图折叠：显 9 格，末格 ink 80% scrim + 「+N」', (tester) async {
+      await tester.pumpWidget(
+        wrap(PostMediaGrid(urls: urls(12), totalCount: 12)),
+      );
+      expect(find.byType(RemoteImage), findsNWidgets(9));
+      expect(find.text('+3'), findsOneWidget);
+      final scrim = tester
+          .widgetList<DecoratedBox>(find.byType(DecoratedBox))
+          .map((w) => w.decoration)
+          .whereType<BoxDecoration>()
+          .where((d) => d.color == AppColors.ink.withAlpha(204));
+      expect(scrim, isNotEmpty);
+    });
+
+    testWidgets('单图折叠形态（Feed 封面 + 总数）：4:3 单格 + 角标胶囊', (tester) async {
+      await tester.pumpWidget(
+        wrap(PostMediaGrid(urls: urls(1), totalCount: 3)),
+      );
+      expect(find.byType(GridView), findsNothing);
+      expect(find.byType(AspectRatio), findsOneWidget);
+      expect(find.text('+2'), findsOneWidget);
+    });
+
+    testWidgets('单图无折余不出角标', (tester) async {
+      await tester.pumpWidget(wrap(PostMediaGrid(urls: urls(1))));
+      expect(find.textContaining('+'), findsNothing);
+    });
+  });
+
+  group('FeedSkeleton（05 §3.7）', () {
+    testWidgets('骨架单元：头部圆 + 4:3 块 + 正文横条，呼吸动效运行', (tester) async {
+      await tester.pumpWidget(wrap(const FeedSkeleton()));
+      await tester.pump(const Duration(milliseconds: 300));
+      expect(find.byType(AspectRatio), findsOneWidget);
+      final fade = tester.widget<FadeTransition>(
+        find
+            .descendant(
+              of: find.byType(FeedSkeleton),
+              matching: find.byType(FadeTransition),
+            )
+            .first,
+      );
+      final controller = fade.opacity as AnimationController;
+      expect(controller.isAnimating, isTrue);
+    });
+
+    testWidgets('系统减弱动态效果：动画静止在 1.0（pumpAndSettle 可收敛）', (tester) async {
+      await tester.pumpWidget(
+        wrap(const FeedSkeleton(), disableAnimations: true),
+      );
+      await tester.pumpAndSettle();
+      final fade = tester.widget<FadeTransition>(
+        find
+            .descendant(
+              of: find.byType(FeedSkeleton),
+              matching: find.byType(FadeTransition),
+            )
+            .first,
+      );
+      expect(fade.opacity.value, 1.0);
+    });
+  });
+}