feat: Week 4 收尾 + 架构治理 — 搜索/家长中心/Feature Flag/Docker/环境配置

架构治理:
- Feature Flag 落地: Cargo.toml [features] default=["diary"] + main.rs cfg 条件编译
- 环境配置统一: AppConfig 类 + --dart-define 注入 + SSE 端口 8080→3000 修复

搜索替代方案 (无 FTS):
- SearchBloc + 标签/心情筛选接入后端 API
- JournalRepository 扩展 mood/tag 筛选参数
- 搜索页 UI 接入实际数据（替换占位文本）

家长中心最小集 (PIPL 合规):
- 后端: parent_service (绑定/查看/导出/删除/解绑) + parent_handler (6 个 API 端点)
- 前端: ParentBloc + ParentPage 功能完整实现
- 绑定孩子、只读查看日记、导出数据、删除数据、解绑

Docker 部署:
- verify.sh 健康检查脚本 (Axum/PG/Redis/OpenAPI 四项检查)

测试修复:
- home_bloc_test / calendar_bloc_test 适配 JournalRepository 新参数

验证: flutter test 84/84 pass, cargo test 76/76 pass, cargo check pass

app/lib/features/parent/bloc/parent_state.dart

@@ -0,0 +1,79 @@
+// 家长中心状态 — ParentBloc 输出的 UI 状态
+
+part of 'parent_bloc.dart';
+
+/// 家长中心状态基类
+sealed class ParentState {
+  const ParentState();
+}
+
+/// 初始状态
+final class ParentInitial extends ParentState {
+  const ParentInitial();
+}
+
+/// 加载中
+final class ParentLoading extends ParentState {
+  const ParentLoading();
+}
+
+/// 孩子列表已加载
+final class ParentChildrenLoaded extends ParentState {
+  final List<ChildBinding> children;
+  const ParentChildrenLoaded(this.children);
+}
+
+/// 孩子日记已加载（只读）
+final class ParentJournalsLoaded extends ParentState {
+  final String childId;
+  final List<Map<String, dynamic>> journals;
+  const ParentJournalsLoaded({
+    required this.childId,
+    required this.journals,
+  });
+}
+
+/// 数据已导出
+final class ParentDataExported extends ParentState {
+  final String childId;
+  final Map<String, dynamic> data;
+  const ParentDataExported({
+    required this.childId,
+    required this.data,
+  });
+}
+
+/// 数据已删除
+final class ParentDataDeleted extends ParentState {
+  final String childId;
+  const ParentDataDeleted(this.childId);
+}
+
+/// 出错
+final class ParentError extends ParentState {
+  final String message;
+  const ParentError(this.message);
+}
+
+// ===== 模型 =====
+
+/// 家长-孩子绑定关系
+class ChildBinding {
+  final String bindingId;
+  final String childId;
+  final DateTime? verifiedAt;
+
+  const ChildBinding({
+    required this.bindingId,
+    required this.childId,
+    this.verifiedAt,
+  });
+
+  factory ChildBinding.fromJson(Map<String, dynamic> json) => ChildBinding(
+        bindingId: json['binding_id'] as String,
+        childId: json['child_id'] as String,
+        verifiedAt: json['verified_at'] != null
+            ? DateTime.tryParse(json['verified_at'] as String)
+            : null,
+      );
+}