feat(app): 老师点评功能 — CommentCreate事件 + CommentBottomSheet + 日记墙点评按钮

app/lib/features/class_/views/class_page.dart

@@ -4,11 +4,14 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
 import 'package:nuanji_app/core/theme/app_colors.dart';
+import 'package:nuanji_app/core/theme/app_radius.dart';
 import 'package:nuanji_app/data/models/journal_entry.dart';
 import 'package:nuanji_app/data/models/school_class.dart';
 import 'package:nuanji_app/data/repositories/class_repository.dart';
 import 'package:nuanji_app/data/repositories/journal_repository.dart';
+import '../../auth/bloc/auth_bloc.dart';
 import '../bloc/class_bloc.dart';
+import '../widgets/comment_bottom_sheet.dart';
 
 /// 班级主页 — 日记墙 + 班级信息
 class ClassPage extends StatelessWidget {
@@ -129,12 +132,12 @@ class _ClassListCard extends StatelessWidget {
       margin: const EdgeInsets.only(bottom: 12),
       elevation: 0,
       shape: RoundedRectangleBorder(
-        borderRadius: BorderRadius.circular(16),
+        borderRadius: AppRadius.mdBorder,
         side: BorderSide(color: colorScheme.outlineVariant),
       ),
       child: InkWell(
         onTap: onTap,
-        borderRadius: BorderRadius.circular(16),
+        borderRadius: AppRadius.mdBorder,
         child: Padding(
           padding: const EdgeInsets.all(16),
           child: Row(
@@ -292,12 +295,12 @@ class _DiaryWallCard extends StatelessWidget {
       margin: const EdgeInsets.only(bottom: 12),
       elevation: 0,
       shape: RoundedRectangleBorder(
-        borderRadius: BorderRadius.circular(16),
+        borderRadius: AppRadius.mdBorder,
         side: BorderSide(color: colorScheme.outlineVariant),
       ),
       child: InkWell(
         onTap: () => context.push('/editor?id=${journal.id}'),
-        borderRadius: BorderRadius.circular(16),
+        borderRadius: AppRadius.mdBorder,
         child: Padding(
           padding: const EdgeInsets.all(16),
           child: Column(
@@ -348,7 +351,7 @@ class _DiaryWallCard extends StatelessWidget {
                   padding: const EdgeInsets.all(8),
                   decoration: BoxDecoration(
                     color: colorScheme.primaryContainer.withValues(alpha: 0.3),
-                    borderRadius: BorderRadius.circular(8),
+                    borderRadius: AppRadius.xsBorder,
                   ),
                   child: Row(
                     children: [
@@ -366,6 +369,36 @@ class _DiaryWallCard extends StatelessWidget {
                   ),
                 ),
               ],
+              // 写评语按钮（仅老师可见）
+              if (_isTeacher(context)) ...[
+                const SizedBox(height: 8),
+                TextButton.icon(
+                  onPressed: () {
+                    showModalBottomSheet(
+                      context: context,
+                      isScrollControlled: true,
+                      builder: (_) => CommentBottomSheet(
+                        journalId: journal.id,
+                        studentName: journal.authorId, // TODO: 替换为真实昵称
+                        onSubmit: (content) {
+                          context.read<ClassBloc>().add(
+                                CommentCreate(
+                                  journalId: journal.id,
+                                  content: content,
+                                ),
+                              );
+                        },
+                      ),
+                    );
+                  },
+                  icon: const Icon(Icons.rate_review_outlined, size: 16),
+                  label: const Text('写评语'),
+                  style: TextButton.styleFrom(
+                    padding: const EdgeInsets.symmetric(horizontal: 12),
+                    minimumSize: const Size(0, 36),
+                  ),
+                ),
+              ],
             ],
           ),
         ),
@@ -373,6 +406,15 @@ class _DiaryWallCard extends StatelessWidget {
     );
   }
 
+  /// 判断当前用户是否是老师
+  bool _isTeacher(BuildContext context) {
+    final authState = context.read<AuthBloc>().state;
+    if (authState is Authenticated) {
+      return authState.user.isTeacher;
+    }
+    return false;
+  }
+
   String _moodEmoji(Mood mood) => switch (mood) {
         Mood.happy => '😊',
         Mood.calm => '😌',
@@ -413,12 +455,12 @@ class _TopicsTab extends StatelessWidget {
           margin: const EdgeInsets.only(bottom: 12),
           elevation: 0,
           shape: RoundedRectangleBorder(
-            borderRadius: BorderRadius.circular(16),
+            borderRadius: AppRadius.mdBorder,
             side: BorderSide(color: colorScheme.outlineVariant),
           ),
           child: InkWell(
             onTap: () => context.push('/editor?topic=${topic.id}'),
-            borderRadius: BorderRadius.circular(16),
+            borderRadius: AppRadius.mdBorder,
             child: Padding(
               padding: const EdgeInsets.all(16),
               child: Column(