feat(app): F8 班级系统 + F9/F10 占位页面

F8 班级系统:
- ClassBloc 状态管理 (班级列表/日记墙/成员/主题/评语)
- 班级主页: 日记墙 + 主题布置 Tab + 成员列表
- 老师管理页: 创建班级 + 布置主题 + 点评入口
- 班级码展示 + 评语卡片

F9 家长功能 (占位):
- 家长中心页面框架: 日记查看/心情统计/使用时间/数据管理
- PIPL 合规提示卡片

F10 搜索/设置 (部分):
- 个人中心: 用户信息 + 角色展示 + 功能入口 + 退出登录
- 搜索页: 标签筛选 + 心情过滤 + 搜索框

验证: flutter analyze 0 error

app/lib/features/search/views/search_page.dart

@@ -1,14 +1,160 @@
-import 'package:flutter/material.dart';
+// 搜索页面 — 日记搜索 + 标签筛选
 
-class SearchPage extends StatelessWidget {
+import 'package:flutter/material.dart';
+import 'package:nuanji_app/core/theme/app_colors.dart';
+import 'package:nuanji_app/data/models/journal_entry.dart';
+
+/// 搜索页面 — 全文搜索日记（Phase 1 占位 UI）
+class SearchPage extends StatefulWidget {
   const SearchPage({super.key});
 
+  @override
+  State<SearchPage> createState() => _SearchPageState();
+}
+
+class _SearchPageState extends State<SearchPage> {
+  final _searchController = TextEditingController();
+  bool _hasSearched = false;
+
+  // Phase 1 占位数据
+  final _recentTags = ['日常', '学校', '旅行', '美食', '读书', '心情'];
+  final _moodFilters = Mood.values;
+
+  @override
+  void dispose() {
+    _searchController.dispose();
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
-    return const Scaffold(
-      body: Center(
-        child: Text('搜索 - 占位页面'),
+    final theme = Theme.of(context);
+    final colorScheme = theme.colorScheme;
+
+    return Scaffold(
+      appBar: AppBar(
+        title: TextField(
+          controller: _searchController,
+          decoration: InputDecoration(
+            hintText: '搜索日记...',
+            hintStyle: theme.textTheme.bodyLarge?.copyWith(
+              color: colorScheme.onSurface.withValues(alpha: 0.4),
+            ),
+            border: InputBorder.none,
+            prefixIcon: const Icon(Icons.search),
+            suffixIcon: _searchController.text.isNotEmpty
+                ? IconButton(
+                    icon: const Icon(Icons.clear),
+                    onPressed: () {
+                      _searchController.clear();
+                      setState(() => _hasSearched = false);
+                    },
+                  )
+                : null,
+          ),
+          textInputAction: TextInputAction.search,
+          onSubmitted: (_) => _doSearch(),
+        ),
+      ),
+      body: _hasSearched
+          ? _buildSearchResults(context, colorScheme)
+          : _buildSuggestions(context, theme, colorScheme),
+    );
+  }
+
+  void _doSearch() {
+    setState(() => _hasSearched = true);
+  }
+
+  Widget _buildSuggestions(BuildContext context, ThemeData theme, ColorScheme colorScheme) {
+    return SingleChildScrollView(
+      padding: const EdgeInsets.all(16),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text('常用标签', style: theme.textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600)),
+          const SizedBox(height: 8),
+          Wrap(
+            spacing: 8,
+            runSpacing: 8,
+            children: _recentTags.map((tag) {
+              return ActionChip(
+                label: Text(tag),
+                onPressed: () {
+                  _searchController.text = tag;
+                  _doSearch();
+                },
+              );
+            }).toList(),
+          ),
+          const SizedBox(height: 24),
+          Text('按心情筛选', style: theme.textTheme.titleSmall?.copyWith(fontWeight: FontWeight.w600)),
+          const SizedBox(height: 12),
+          Wrap(
+            spacing: 12,
+            runSpacing: 12,
+            children: _moodFilters.map((mood) {
+              final color = AppColors.moodColors[mood.value] ?? colorScheme.primary;
+              return GestureDetector(
+                onTap: () {
+                  _searchController.text = _moodLabel(mood);
+                  _doSearch();
+                },
+                child: Column(
+                  children: [
+                    Container(
+                      width: 48,
+                      height: 48,
+                      decoration: BoxDecoration(
+                        shape: BoxShape.circle,
+                        color: color.withValues(alpha: 0.15),
+                      ),
+                      alignment: Alignment.center,
+                      child: Text(_moodEmoji(mood), style: const TextStyle(fontSize: 24)),
+                    ),
+                    const SizedBox(height: 4),
+                    Text(_moodLabel(mood), style: theme.textTheme.labelSmall),
+                  ],
+                ),
+              );
+            }).toList(),
+          ),
+        ],
       ),
     );
   }
+
+  Widget _buildSearchResults(BuildContext context, ColorScheme colorScheme) {
+    return Center(
+      child: Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          Icon(Icons.search_off_rounded, size: 48, color: colorScheme.onSurface.withValues(alpha: 0.2)),
+          const SizedBox(height: 12),
+          Text(
+            'Phase 1: 搜索功能待 Isar FTS 集成',
+            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+              color: colorScheme.onSurface.withValues(alpha: 0.5),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  String _moodEmoji(Mood mood) => switch (mood) {
+        Mood.happy => '😊',
+        Mood.calm => '😌',
+        Mood.sad => '😢',
+        Mood.angry => '😠',
+        Mood.thinking => '🤔',
+      };
+
+  String _moodLabel(Mood mood) => switch (mood) {
+        Mood.happy => '开心',
+        Mood.calm => '平静',
+        Mood.sad => '难过',
+        Mood.angry => '生气',
+        Mood.thinking => '思考',
+      };
 }