feat: 首付分期功能实现 - 项目初始化提交

- 添加首付分期功能相关表结构和数据
- 实现首付分期策略管理
- 添加首付分期支付详情管理
- 完善项目相关功能模块
- 修复外键类型问题
- 添加相关初始化脚本和文档

script/sql/update/update_5.1.2-5.2.0.sql

@@ -0,0 +1,5 @@
+ALTER TABLE sys_dept ADD dept_category VARCHAR(100) DEFAULT NULL COMMENT '部门类别编码';
+ALTER TABLE sys_post ADD dept_id BIGINT(20) NOT NULL COMMENT '部门id', ADD post_category VARCHAR(100) DEFAULT NULL COMMENT '岗位类别编码';
+UPDATE sys_post SET dept_id = 100;
+UPDATE sys_post SET dept_id = 103 where post_id = 1;
+UPDATE sys_menu SET menu_name = 'SnailJob控制台', path = 'snailjob', component = 'monitor/snailjob/index', perms = 'monitor:snailjob:list', remark = 'SnailJob控制台菜单' WHERE menu_id = 120;