feat(auth): add Casbin RBAC and user activity tracking

Integrate Casbin for role-based access control with admin routes for role management. Add user activity logging service to track login and refresh events. Refactor audit service to use AI-based content moderation.

configs/config.yaml

@@ -201,3 +201,22 @@ grpc:
   tls_enabled: false
   tls_cert_file: ""
   tls_key_file: ""
+
+# Casbin RBAC权限系统配置
+# 环境变量:
+#   APP_CASBIN_MODEL_PATH, APP_CASBIN_AUTO_SAVE, APP_CASBIN_AUTO_LOAD
+#   APP_CASBIN_ENABLE_CACHE, APP_CASBIN_CACHE_TTL
+casbin:
+  model_path: "./configs/casbin/model.conf"
+  auto_save: true
+  auto_load: true
+  enable_cache: true
+  cache_ttl: 300
+  skip_routes:
+    - /health
+    - /api/v1/auth/login
+    - /api/v1/auth/register
+    - /api/v1/auth/check-username
+    - /api/v1/auth/password/send-code
+    - /api/v1/auth/password/reset
+    - /api/v1/auth/refresh