feat: initialize ERP base platform (extracted from HMS)

- Stripped 11 business crates (health, ai, dialysis, plugins)
- Cleaned AppState, AppConfig, main.rs from business coupling
- Reduced migrations from 169 to 53 (base-only)
- Removed health_provider trait from erp-core
- Removed business integration tests
- Removed gateway rate limiting middleware
- Base capabilities: auth, RBAC, JWT, config, workflow, message, plugin, audit, crypto, RLS, multi-tenant

Cargo check: OK
Cargo test: OK

docker/nginx/ssl/.gitignore

@@ -0,0 +1,3 @@
+*
+!.gitkeep
+!.gitignore

docker/nginx/ssl/.gitkeep

@@ -0,0 +1,8 @@
+# 将 SSL 证书放置在此目录
+# 必需文件: fullchain.pem + privkey.pem
+# 生产环境建议使用 Let's Encrypt 或云服务商证书管理
+#
+# Let's Encrypt 示例:
+#   certbot certonly --standalone -d your-domain.com
+#   cp /etc/letsencrypt/live/your-domain.com/fullchain.pem .
+#   cp /etc/letsencrypt/live/your-domain.com/privkey.pem .