fix(diary): 添加事务 — create_class/join_class/parent 删除原子化

- create_class: 班级创建 + 老师成员插入包裹在 db.transaction() 中
- join_class: 成员插入 + member_count 更新包裹在事务中
- delete_child_data: PIPL 删除权 — 逐条软删除包裹在事务中（避免部分删除）
- DiaryError: 添加 From<TransactionError<DiaryError>> 支持事务闭包

审计 ID: B-07, B-11, 8a-C03

crates/erp-diary/src/error.rs

@@ -106,6 +106,18 @@ impl From<sea_orm::DbErr> for DiaryError {
     }
 }
 
+/// 支持 db.transaction() 闭包的错误转换
+impl From<sea_orm::TransactionError<DiaryError>> for DiaryError {
+    fn from(err: sea_orm::TransactionError<DiaryError>) -> Self {
+        match err {
+            sea_orm::TransactionError::Connection(db_err) => {
+                DiaryError::Internal(db_err.to_string())
+            }
+            sea_orm::TransactionError::Transaction(inner) => inner,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/erp-diary/src/service/class_service.rs

@@ -3,7 +3,7 @@
 use chrono::{Months, Utc};
 use sea_orm::{
     ActiveModelTrait, ColumnTrait, DatabaseConnection, EntityTrait, QueryFilter,
-    Set,
+    Set, TransactionTrait,
 };
 use uuid::Uuid;
 
@@ -37,42 +37,49 @@ impl ClassService {
         // 过期时间：6 个月后
         let expires_at = now.checked_add_months(Months::new(6));
 
-        // 创建班级记录
-        let class_model = school_class::ActiveModel {
-            id: Set(id),
-            tenant_id: Set(tenant_id),
-            name: Set(name),
-            school_name: Set(school_name),
-            teacher_id: Set(teacher_id),
-            class_code: Set(class_code.clone()),
-            member_count: Set(1), // 老师自动计入
-            is_active: Set(true),
-            expires_at: Set(expires_at),
-            created_at: Set(now),
-            updated_at: Set(now),
-            created_by: Set(teacher_id),
-            updated_by: Set(teacher_id),
-            deleted_at: Set(None),
-            version: Set(1),
-        };
-        let inserted_class = class_model.insert(db).await?;
+        // 事务：创建班级 + 老师自动加入（原子操作，保证一致性）
+        let inserted_class = db
+            .transaction::<_, school_class::Model, DiaryError>(|txn| {
+                Box::pin(async move {
+                    let class_model = school_class::ActiveModel {
+                        id: Set(id),
+                        tenant_id: Set(tenant_id),
+                        name: Set(name),
+                        school_name: Set(school_name),
+                        teacher_id: Set(teacher_id),
+                        class_code: Set(class_code),
+                        member_count: Set(1), // 老师自动计入
+                        is_active: Set(true),
+                        expires_at: Set(expires_at),
+                        created_at: Set(now),
+                        updated_at: Set(now),
+                        created_by: Set(teacher_id),
+                        updated_by: Set(teacher_id),
+                        deleted_at: Set(None),
+                        version: Set(1),
+                    };
+                    let inserted = class_model.insert(txn).await?;
 
-        // 自动将老师加入成员表
-        let member_model = class_member::ActiveModel {
-            class_id: Set(id),
-            user_id: Set(teacher_id),
-            tenant_id: Set(tenant_id),
-            role: Set("teacher".to_string()),
-            nickname: Set(None),
-            joined_at: Set(now),
-            created_at: Set(now),
-            updated_at: Set(now),
-            created_by: Set(teacher_id),
-            updated_by: Set(teacher_id),
-            deleted_at: Set(None),
-            version: Set(1),
-        };
-        member_model.insert(db).await?;
+                    let member_model = class_member::ActiveModel {
+                        class_id: Set(id),
+                        user_id: Set(teacher_id),
+                        tenant_id: Set(tenant_id),
+                        role: Set("teacher".to_string()),
+                        nickname: Set(None),
+                        joined_at: Set(now),
+                        created_at: Set(now),
+                        updated_at: Set(now),
+                        created_by: Set(teacher_id),
+                        updated_by: Set(teacher_id),
+                        deleted_at: Set(None),
+                        version: Set(1),
+                    };
+                    member_model.insert(txn).await?;
+
+                    Ok(inserted)
+                })
+            })
+            .await?;
 
         // 发布 ClassCreated 事件
         event_bus
@@ -175,31 +182,38 @@ impl ClassService {
             return Err(DiaryError::BadRequest("已是班级成员".to_string()));
         }
 
-        // 5. 创建成员记录
-        let member_model = class_member::ActiveModel {
-            class_id: Set(class_id),
-            user_id: Set(user_id),
-            tenant_id: Set(tenant_id),
-            role: Set("student".to_string()),
-            nickname: Set(nickname),
-            joined_at: Set(now),
-            created_at: Set(now),
-            updated_at: Set(now),
-            created_by: Set(user_id),
-            updated_by: Set(user_id),
-            deleted_at: Set(None),
-            version: Set(1),
-        };
-        member_model.insert(db).await?;
-
-        // 6. 更新 member_count
+        // 5. 事务：创建成员记录 + 更新 member_count（原子操作）
         let current_count = class_model.member_count;
         let current_version = class_model.version;
-        let mut active_class: school_class::ActiveModel = class_model.into();
-        active_class.member_count = Set(current_count + 1);
-        active_class.updated_at = Set(now);
-        active_class.version = Set(current_version + 1);
-        let updated_class = active_class.update(db).await?;
+        let updated_class = db
+            .transaction::<_, school_class::Model, DiaryError>(|txn| {
+                Box::pin(async move {
+                    let member_model = class_member::ActiveModel {
+                        class_id: Set(class_id),
+                        user_id: Set(user_id),
+                        tenant_id: Set(tenant_id),
+                        role: Set("student".to_string()),
+                        nickname: Set(nickname),
+                        joined_at: Set(now),
+                        created_at: Set(now),
+                        updated_at: Set(now),
+                        created_by: Set(user_id),
+                        updated_by: Set(user_id),
+                        deleted_at: Set(None),
+                        version: Set(1),
+                    };
+                    member_model.insert(txn).await?;
+
+                    let mut active_class: school_class::ActiveModel = class_model.into();
+                    active_class.member_count = Set(current_count + 1);
+                    active_class.updated_at = Set(now);
+                    active_class.version = Set(current_version + 1);
+                    let updated = active_class.update(txn).await?;
+
+                    Ok(updated)
+                })
+            })
+            .await?;
 
         // 7. 成功加入 → 清除错误计数
         if let Some(redis_client) = redis {

crates/erp-diary/src/service/parent_service.rs

@@ -3,7 +3,7 @@
 use chrono::Utc;
 use sea_orm::{
     ActiveModelTrait, ColumnTrait, DatabaseConnection, EntityTrait, PaginatorTrait,
-    QueryFilter, QueryOrder, Set,
+    QueryFilter, QueryOrder, Set, TransactionTrait,
 };
 use uuid::Uuid;
 
@@ -176,15 +176,22 @@ impl ParentService {
         let count = journals.len();
         let now = Utc::now();
 
-        for journal in journals {
-            let current_version = journal.version;
-            let mut active: journal_entry::ActiveModel = journal.into();
-            active.deleted_at = Set(Some(now));
-            active.updated_at = Set(now);
-            active.updated_by = Set(parent_id);
-            active.version = Set(current_version + 1);
-            active.update(db).await?;
-        }
+        // 事务：软删除所有日记（PIPL 删除权 — 原子操作，避免部分删除）
+        db.transaction::<_, (), DiaryError>(|txn| {
+            Box::pin(async move {
+                for journal in journals {
+                    let current_version = journal.version;
+                    let mut active: journal_entry::ActiveModel = journal.into();
+                    active.deleted_at = Set(Some(now));
+                    active.updated_at = Set(now);
+                    active.updated_by = Set(parent_id);
+                    active.version = Set(current_version + 1);
+                    active.update(txn).await?;
+                }
+                Ok(())
+            })
+        })
+        .await?;
 
         event_bus
             .publish(