feat(todo): 新增多人待办清单后端

- 新增 t_todo 表（user_id 隔离 + 逻辑删除），增量脚本 sql/delta_todo.sql
- entity/mapper/service/controller 四层，复用 MyBatis-Plus 与 Result
- /todo/** 纳入 JWT 认证，user_id 一律由 token 解析，禁止前端传入

sql/delta_todo.sql

@@ -0,0 +1,55 @@
+-- ============================================================
+-- 待办清单模块（t_todo）
+-- 数据库: freedom_db
+-- 用途:  多人待办清单，数据按 user_id 隔离，每个登录用户只能管理自己的待办
+-- 说明:  可重复执行（CREATE TABLE IF NOT EXISTS / 幂等 INSERT 判断）
+--        执行后需重新登录系统（或退出登录）刷新菜单缓存方可看到新菜单
+-- ============================================================
+
+USE `freedom_db`;
+
+-- 1. 待办清单数据表
+CREATE TABLE IF NOT EXISTS `t_todo` (
+  `id`          BIGINT       NOT NULL AUTO_INCREMENT COMMENT '主键',
+  `user_id`     BIGINT       NOT NULL COMMENT '所属用户ID（关联 t_sys_user.id）',
+  `title`       VARCHAR(200) NOT NULL COMMENT '标题',
+  `status`      TINYINT      DEFAULT 0 COMMENT '状态：0未完成 1已完成',
+  `priority`    TINYINT      DEFAULT 2 COMMENT '优先级：1低 2中 3高',
+  `due_date`    DATE         DEFAULT NULL COMMENT '截止日期',
+  `remark`      VARCHAR(500) DEFAULT NULL COMMENT '备注',
+  `create_by`   VARCHAR(50)  DEFAULT NULL COMMENT '创建者',
+  `create_date` DATETIME     DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
+  `update_by`   VARCHAR(50)  DEFAULT NULL COMMENT '更新者',
+  `update_date` DATETIME     DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',
+  `del_flag`    TINYINT      DEFAULT 0 COMMENT '删除标记',
+  PRIMARY KEY (`id`),
+  KEY `idx_todo_user_status` (`user_id`, `status`, `del_flag`),
+  KEY `idx_todo_user_due` (`user_id`, `due_date`)
+) ENGINE=InnoDB AUTO_INCREMENT=1000 DEFAULT CHARSET=utf8mb4 COMMENT='待办清单表';
+
+-- 2. 菜单权限：一级菜单「待办」
+INSERT INTO `t_sys_permission`
+  (`parent_id`, `permission_code`, `permission_name`, `permission_desc`, `level`, `icon`, `url`, `component`, `sort`, `create_by`, `create_date`, `del_flag`)
+SELECT 0, 'todo', '待办', '多人待办清单', 1, 'md-checkmark-circle', '', '', 10, 'admin', NOW(), 0
+FROM DUAL
+WHERE NOT EXISTS (SELECT 1 FROM `t_sys_permission` WHERE `permission_code` = 'todo' AND `del_flag` = 0);
+
+-- 3. 菜单权限：二级菜单「待办清单」
+SET @todo_parent_id = (SELECT `id` FROM `t_sys_permission` WHERE `permission_code` = 'todo' AND `del_flag` = 0 ORDER BY `id` LIMIT 1);
+
+INSERT INTO `t_sys_permission`
+  (`parent_id`, `permission_code`, `permission_name`, `permission_desc`, `level`, `icon`, `url`, `component`, `sort`, `create_by`, `create_date`, `del_flag`)
+SELECT @todo_parent_id, 'todo:list', '待办清单', '个人待办事项的增删改与完成状态维护', 2, 'md-list-box', '/todo/list', '/todo/todo-list', 1, 'admin', NOW(), 0
+FROM DUAL
+WHERE NOT EXISTS (SELECT 1 FROM `t_sys_permission` WHERE `permission_code` = 'todo:list' AND `del_flag` = 0);
+
+-- 4. 角色授权：给所有现有角色挂上新菜单（幂等）
+INSERT INTO `t_sys_role_permission` (`role_id`, `permission_id`, `create_by`, `create_date`)
+SELECT r.`id`, p.`id`, 'admin', NOW()
+FROM `t_sys_role` r
+JOIN `t_sys_permission` p ON p.`permission_code` IN ('todo', 'todo:list') AND p.`del_flag` = 0
+WHERE r.`del_flag` = 0
+  AND NOT EXISTS (
+    SELECT 1 FROM `t_sys_role_permission` rp
+    WHERE rp.`role_id` = r.`id` AND rp.`permission_id` = p.`id`
+  );