refactor: de-submodule rlz backend and integrate all source code

Move rlz/ backend from git submodule to first-class source tree.
Includes all RuoYi 3.8.3 backend source, mapper XMLs, SQL scripts,
Dockerfile, and build configs. Also adds frontend enhancements:

- Order management: status filters, refund review, settlement (Issue #14)
- Hospital management: level/description/image fields (Issue #16)
- User management: type filter, userLevel, stats endpoint (Issue #17)
- Dev environment: application-dev.yml for rlz_dev database
- CI/CD: Drone pipeline configuration (.drone.yml)
- Mini program: API config extraction (coupon/utils/config.js)

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

coupon/utils/config.js

@@ -0,0 +1,9 @@
+// 环境配置 - 切换环境只需修改此文件
+const config = {
+  // 开发环境（本地后端，需改为本机IP）
+  // baseUrl: 'http://192.168.1.100:8039',
+  // 生产环境
+  baseUrl: 'http://101.43.95.130:8039',
+}
+
+module.exports = config