feat(ai): 知识库 V2 菜单迁移 + 文本切片器 + 前端路由权限

- 新增迁移 000168：在 AI 知识库同级添加「知识库 V2」菜单，绑定 admin 角色
- 新增 document/chunker.rs：固定大小 + overlap 文本切片器（5 单元测试）
- 前端 routeConfig 添加 /health/ai-knowledge-v2 权限声明
- App.tsx validateRouteCoverage 补充 v2 路径

crates/erp-server/migration/src/lib.rs

@@ -174,6 +174,7 @@ mod m20260526_000164_ai_prompt_add_analysis_type;
 mod m20260526_000165_ai_prompt_fix_analysis_type;
 mod m20260526_000166_create_ai_knowledge_bases;
 mod m20260526_000167_create_ai_knowledge_documents;
+mod m20260527_000168_ai_knowledge_v2_menu;
 
 pub struct Migrator;
 
@@ -355,6 +356,7 @@ impl MigratorTrait for Migrator {
             Box::new(m20260526_000165_ai_prompt_fix_analysis_type::Migration),
             Box::new(m20260526_000166_create_ai_knowledge_bases::Migration),
             Box::new(m20260526_000167_create_ai_knowledge_documents::Migration),
+            Box::new(m20260527_000168_ai_knowledge_v2_menu::Migration),
         ]
     }
 }

crates/erp-server/migration/src/m20260527_000168_ai_knowledge_v2_menu.rs

@@ -0,0 +1,62 @@
+use sea_orm_migration::prelude::*;
+
+#[derive(DeriveMigrationName)]
+pub struct Migration;
+
+#[async_trait::async_trait]
+impl MigrationTrait for Migration {
+    async fn up(&self, manager: &SchemaManager) -> Result<(), DbErr> {
+        // 在"AI 知识库"同级位置添加"知识库 V2"菜单
+        // parent_id 取旧 ai-knowledge 菜单的 parent_id
+        let sql = r#"
+            INSERT INTO sys_menu (id, parent_id, name, path, icon, sort, permission, component, is_external, is_cached, status, visible, created_at, updated_at, deleted_at)
+            SELECT
+                gen_random_uuid(),
+                parent_id,
+                '知识库 V2',
+                '/health/ai-knowledge-v2',
+                'DatabaseOutlined',
+                54,
+                'ai.knowledge.list',
+                'ai/KnowledgeV2Page',
+                false,
+                false,
+                'active',
+                true,
+                now(),
+                now(),
+                NULL
+            FROM sys_menu
+            WHERE path = '/health/ai-knowledge' AND deleted_at IS NULL
+            LIMIT 1
+            ON CONFLICT DO NOTHING
+        "#;
+
+        manager.get_connection().execute_unprepared(sql).await?;
+
+        // 绑定到 admin 角色
+        let role_sql = r#"
+            INSERT INTO sys_role_menu (role_id, menu_id)
+            SELECT r.id, m.id
+            FROM sys_role r, sys_menu m
+            WHERE r.code = 'admin' AND r.deleted_at IS NULL
+              AND m.path = '/health/ai-knowledge-v2' AND m.deleted_at IS NULL
+            ON CONFLICT DO NOTHING
+        "#;
+
+        manager
+            .get_connection()
+            .execute_unprepared(role_sql)
+            .await?;
+
+        Ok(())
+    }
+
+    async fn down(&self, manager: &SchemaManager) -> Result<(), DbErr> {
+        manager
+            .get_connection()
+            .execute_unprepared("DELETE FROM sys_menu WHERE path = '/health/ai-knowledge-v2'")
+            .await?;
+        Ok(())
+    }
+}