feat(db): add migrations for RBAC, diagnostic, messaging, attendance, leave, invitation codes

- 0011: RBAC role flags and seed data

- 0012: diagnostic grade_id

- 0013: message recall

- 0014: message templates

- 0015: group messages and message reports/blocks

- 0016: invitation codes

- 0017: draft device sync

- 0018: attendance status reason

- 0019: attendance warning thresholds

- 0020: leave requests

- 0021: attendance period

drizzle/0020_leave_requests.sql

@@ -0,0 +1,53 @@
+-- 0020_leave_requests.sql
+-- L-5 在线请假流程：创建 leave_requests 表。
+
+CREATE TABLE IF NOT EXISTS `leave_requests` (
+  `id` varchar(128) NOT NULL,
+  `student_id` varchar(128) NOT NULL,
+  `requester_id` varchar(128) NOT NULL,
+  `class_id` varchar(128) NOT NULL,
+  `leave_type` enum('sick','personal','family','other') NOT NULL,
+  `start_date` date NOT NULL,
+  `end_date` date NOT NULL,
+  `reason` text NOT NULL,
+  `status` enum('pending','approved','rejected','cancelled') NOT NULL DEFAULT 'pending',
+  `reviewer_id` varchar(128) DEFAULT NULL,
+  `review_comment` text,
+  `reviewed_at` timestamp NULL DEFAULT NULL,
+  `attendance_synced` boolean NOT NULL DEFAULT false,
+  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  `updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  PRIMARY KEY (`id`),
+  KEY `leave_requests_student_idx` (`student_id`),
+  KEY `leave_requests_requester_idx` (`requester_id`),
+  KEY `leave_requests_class_idx` (`class_id`),
+  KEY `leave_requests_status_idx` (`status`),
+  KEY `leave_requests_reviewer_idx` (`reviewer_id`),
+  KEY `leave_requests_class_status_idx` (`class_id`, `status`),
+  KEY `leave_requests_student_status_idx` (`student_id`, `status`),
+  CONSTRAINT `lr_c_fk` FOREIGN KEY (`class_id`) REFERENCES `classes` (`id`) ON DELETE CASCADE,
+  CONSTRAINT `lr_s_fk` FOREIGN KEY (`student_id`) REFERENCES `users` (`id`) ON DELETE CASCADE,
+  CONSTRAINT `lr_rq_fk` FOREIGN KEY (`requester_id`) REFERENCES `users` (`id`) ON DELETE CASCADE,
+  CONSTRAINT `lr_rv_fk` FOREIGN KEY (`reviewer_id`) REFERENCES `users` (`id`) ON DELETE SET NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
+
+-- 为 builtin 角色注入新权限（INSERT IGNORE 幂等）
+-- admin：三个权限全有
+INSERT IGNORE INTO `role_permissions` (`role_id`, `permission`)
+  SELECT id, 'leave_request:create' FROM `roles` WHERE `name` = 'admin'
+  UNION ALL SELECT id, 'leave_request:read' FROM `roles` WHERE `name` = 'admin'
+  UNION ALL SELECT id, 'leave_request:review' FROM `roles` WHERE `name` = 'admin'
+  -- teacher：read + review（班主任审批本班请假）
+  UNION ALL SELECT id, 'leave_request:read' FROM `roles` WHERE `name` = 'teacher'
+  UNION ALL SELECT id, 'leave_request:review' FROM `roles` WHERE `name` = 'teacher'
+  -- parent：create + read（代子女提交、查看子女请假记录）
+  UNION ALL SELECT id, 'leave_request:create' FROM `roles` WHERE `name` = 'parent'
+  UNION ALL SELECT id, 'leave_request:read' FROM `roles` WHERE `name` = 'parent'
+  -- student：create + read（本人提交、查看本人请假记录）
+  UNION ALL SELECT id, 'leave_request:create' FROM `roles` WHERE `name` = 'student'
+  UNION ALL SELECT id, 'leave_request:read' FROM `roles` WHERE `name` = 'student'
+  -- grade_head / teaching_head：read + review（年级主任/教务主任可审批）
+  UNION ALL SELECT id, 'leave_request:read' FROM `roles` WHERE `name` = 'grade_head'
+  UNION ALL SELECT id, 'leave_request:review' FROM `roles` WHERE `name` = 'grade_head'
+  UNION ALL SELECT id, 'leave_request:read' FROM `roles` WHERE `name` = 'teaching_head'
+  UNION ALL SELECT id, 'leave_request:review' FROM `roles` WHERE `name` = 'teaching_head';