feat: initialize Nuanji (Warm Notes) project

- Base platform from base.git (ERP base: auth, core, config, message, workflow, plugin)
- Created erp-diary module skeleton (lib.rs, dto.rs, error.rs, event.rs, state.rs)
- Integrated erp-diary into workspace and erp-server
- Added DiaryModule registration in main.rs
- Added DiaryState FromRef in state.rs
- Diary routes mounted (empty routes, ready for implementation)
- Product design spec v1.2 preserved in docs/
- Implementation plan preserved in plans/

Cargo check: OK
Cargo test: OK (78+ base tests passing)

crates/erp-diary/src/event.rs

@@ -0,0 +1,61 @@
+// erp-diary 事件定义
+
+/// 日记模块领域事件
+pub enum DiaryEvent {
+    /// 日记创建
+    JournalCreated {
+        journal_id: uuid::Uuid,
+        author_id: uuid::Uuid,
+        class_id: Option<uuid::Uuid>,
+    },
+    /// 日记更新
+    JournalUpdated {
+        journal_id: uuid::Uuid,
+        author_id: uuid::Uuid,
+        version: i32,
+    },
+    /// 日记删除
+    JournalDeleted {
+        journal_id: uuid::Uuid,
+        author_id: uuid::Uuid,
+    },
+    /// 日记分享到班级
+    JournalShared {
+        journal_id: uuid::Uuid,
+        author_id: uuid::Uuid,
+        class_id: uuid::Uuid,
+    },
+    /// 班级创建
+    ClassCreated {
+        class_id: uuid::Uuid,
+        teacher_id: uuid::Uuid,
+    },
+    /// 学生加入班级
+    StudentJoinedClass {
+        class_id: uuid::Uuid,
+        student_id: uuid::Uuid,
+    },
+    /// 老师布置主题
+    TopicAssigned {
+        topic_id: uuid::Uuid,
+        class_id: uuid::Uuid,
+        teacher_id: uuid::Uuid,
+    },
+    /// 老师点评
+    CommentCreated {
+        comment_id: uuid::Uuid,
+        journal_id: uuid::Uuid,
+        teacher_id: uuid::Uuid,
+        student_id: uuid::Uuid,
+    },
+    /// 家长绑定孩子
+    ParentBound {
+        parent_id: uuid::Uuid,
+        child_id: uuid::Uuid,
+    },
+    /// 成就解锁
+    AchievementUnlocked {
+        user_id: uuid::Uuid,
+        achievement_id: String,
+    },
+}