新增：帖子详情页真实数据整页替换——四态/真九宫格大图/评论区/关注双态，Feed 导航与互动全接线，demo 详情退役（T3-15/16）

- post_detail_page 整页重写：内存副本先渲染 + getPost 拉新、四态
 （loading/error+重试/ready/40403 提示后返回 Feed 并刷新）；媒体全量
  ——单图原比例（高度钳制 [0.75w,1.33w]）、多图真九宫格（D11 轮播
  弃用，本单裁定）+ InteractiveViewer 全屏大图（03 号拍板 E）
- 评论区：游标列表触底补页 + 底部输入条创建（幂等键在数据层）+
  仅本人评论渲染删除入口（40301/40404 服务端兜底）；成败埋点对
 （durationMs 取输入会话起点、attemptSeq 会话内递增）；CommentTile
  升共享组件（@ 回复前缀呈现、降级作者「宠友」占位）
- 关注双态钮（tonal ＋关注 / Outlined 已关注 + 取关确认）乐观翻转、
  回滚零动画 + SnackBar，user_followed/unfollowed(post_detail) 挂接；
  本人帖不渲染
- Feed 接通：整卡与评论钮导航详情（T3-14 占位提示移除）、点赞/收藏
  接共享 ToggleSync（详情与卡片同一实例跨页一致）、toggleError
  一次性 SnackBar 消费
- 主壳/装配：openPost 按 postId push；create demo 流不再导航已退役的
  demo 详情（发布页真实化留 T3-17）；AppState 在 post_detail/Feed 面
  消费清零
- compose 冒烟（env 门控默认跳过）：真链路发帖/点赞幂等/收藏/评论/
  删评一轮 + 断网点赞回滚（生产 ApiClient 异常链）

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

test/features/home/home_page_test.dart

@@ -8,6 +8,7 @@ import 'package:patbond_flutter/core/widgets/feed_skeleton.dart';
 import 'package:patbond_flutter/core/widgets/inline_error_banner.dart';
 import 'package:patbond_flutter/core/widgets/post_card.dart';
 import 'package:patbond_flutter/features/community/community_controller.dart';
+import 'package:patbond_flutter/features/community/community_interaction_analytics.dart';
 import 'package:patbond_flutter/features/community/community_models.dart';
 import 'package:patbond_flutter/features/community/feed_analytics.dart';
 import 'package:patbond_flutter/features/home/home_page.dart';
@@ -39,15 +40,22 @@ void main() {
   late List<(String, Map<String, dynamic>?)> events;
   late FeedAnalytics analytics;
   late int createTaps;
+  late List<String> openedPosts;
 
   setUp(() {
     repository = FakeCommunityRepository();
-    controller = CommunityController(repository: repository);
     events = [];
+    controller = CommunityController(
+      repository: repository,
+      interactionAnalytics: CommunityInteractionAnalytics(
+        (name, [props]) async => events.add((name, props)),
+      ),
+    );
     analytics = FeedAnalytics(
       (name, [props]) async => events.add((name, props)),
     );
     createTaps = 0;
+    openedPosts = [];
   });
 
   List<Map<String, dynamic>?> eventsNamed(String name) =>
@@ -65,6 +73,7 @@ void main() {
             isActive: isActive,
             onOpenServices: (_) {},
             onOpenCreate: () => createTaps++,
+            onOpenPost: openedPosts.add,
           ),
         ),
       ),
@@ -361,7 +370,7 @@ void main() {
     expect(eventsNamed('feed_viewed'), hasLength(2));
   });
 
-  testWidgets('T3-14 取舍：整卡点按提示详情接入中（不导航 demo 详情）', (tester) async {
+  testWidgets('T3-15 导航接通：整卡与评论钮点按回调 onOpenPost（占位提示移除）', (tester) async {
     repository.onFeed = (_, _) async => feedPage([textCard('p-1')]);
 
     await pumpHome(tester);
@@ -371,7 +380,72 @@ void main() {
 
     await tester.tap(find.text('动态内容 p-1'));
     await tester.pump();
-    expect(find.text('帖子详情正在接入真实数据，敬请期待'), findsOneWidget);
+    expect(find.text('帖子详情正在接入真实数据，敬请期待'), findsNothing);
+    expect(openedPosts, ['p-1']);
+
+    await tester.tap(find.byIcon(Icons.chat_bubble_outline));
+    await tester.pump();
+    expect(openedPosts, ['p-1', 'p-1']);
+  });
+
+  testWidgets('T3-16 互动接线：点赞乐观翻转即时显示，成功报 post_liked(source=feed)', (
+    tester,
+  ) async {
+    repository.onFeed = (_, _) async => feedPage([
+      FeedCard.fromJson({
+        ...sampleFeedCardJson(likeCount: 6),
+        'coverImage': null,
+        'mediaCount': 0,
+      }),
+    ]);
+    final like = Completer<LikeState>();
+    repository.onLikeToggle = (_, _) => like.future;
+
+    await pumpHome(tester);
+    await tester.pumpAndSettle();
+    await tester.drag(list(), const Offset(0, -800));
+    await tester.pumpAndSettle();
+
+    await tester.tap(find.byIcon(Icons.favorite_border));
+    await tester.pump();
+    // 乐观翻转：请求未回已 +1（同帧反馈）。
+    expect(find.text('7'), findsOneWidget);
+    expect(repository.calls, contains('like:p-1'));
+
+    like.complete(const LikeState(liked: true, likeCount: 7));
+    await tester.pumpAndSettle();
+    expect(eventsNamed('post_liked'), [
+      {'source': 'feed'},
+    ]);
+    expect(find.text('7'), findsOneWidget);
+  });
+
+  testWidgets('T3-16 互动接线：点赞失败回滚 + SnackBar「操作失败，请重试」', (tester) async {
+    repository.onFeed = (_, _) async => feedPage([
+      FeedCard.fromJson({
+        ...sampleFeedCardJson(likeCount: 6),
+        'coverImage': null,
+        'mediaCount': 0,
+      }),
+    ]);
+    final like = Completer<LikeState>();
+    repository.onLikeToggle = (_, _) => like.future;
+
+    await pumpHome(tester);
+    await tester.pumpAndSettle();
+    await tester.drag(list(), const Offset(0, -800));
+    await tester.pumpAndSettle();
+
+    await tester.tap(find.byIcon(Icons.favorite_border));
+    await tester.pump();
+    expect(find.text('7'), findsOneWidget);
+
+    like.completeError(const ApiNetworkException());
+    await tester.pumpAndSettle();
+    // 回滚成对恢复 + SnackBar；不报 post_liked。
+    expect(find.text('6'), findsOneWidget);
+    expect(find.text('操作失败，请重试'), findsOneWidget);
+    expect(eventsNamed('post_liked'), isEmpty);
   });
 
   testWidgets('搜索词过滤已加载卡片；无命中显搜索空态', (tester) async {