chore: 添加数据库资源和需求文档

- 新增数据库连接配置 (db_info)
- 添加 DDL 编辑需求文档
- 添加 TODO 待办事项

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/resources/db_info/44cf2f22-fccb-4dd0-92fb-02d613ce2624.json

@@ -0,0 +1,22 @@
+{
+  "database_id": "44cf2f22-fccb-4dd0-92fb-02d613ce2624",
+  "database_name": "1231",
+  "db_type": "mysql",
+  "tables": [
+    {
+      "id": "042fb35c-9023-40ed-8d3a-cec24f0709a2",
+      "database_id": "44cf2f22-fccb-4dd0-92fb-02d613ce2624",
+      "parent_table": "scores",
+      "sub_table_name": "scores",
+      "sub_table_comment": "",
+      "mapping_type": "",
+      "relation_field": "",
+      "relation_type": "",
+      "fields": null,
+      "ddl": "CREATE TABLE `scores` (\n  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,\n  `student_id` int(10) unsigned NOT NULL,\n  `subject` varchar(50) NOT NULL COMMENT '科目',\n  `score` double DEFAULT NULL COMMENT '分数',\n  `teacher_id` int(10) unsigned DEFAULT NULL,\n  `exam_date` date DEFAULT NULL COMMENT '考试日期',\n  `created_at` datetime DEFAULT CURRENT_TIMESTAMP,\n  PRIMARY KEY (`id`)\n) ENGINE=InnoDB AUTO_INCREMENT=48 DEFAULT CHARSET=utf8mb4",
+      "created_at": "2026-03-07T09:59:48.436+08:00",
+      "updated_at": "2026-03-07T09:59:48.436+08:00"
+    }
+  ],
+  "updated_at": "2026-03-07T09:59:48.4882963+08:00"
+}