feat: add Swagger UI docs, custom CORS middleware, and request logging

- Add Swagger UI files and updated API spec for Family Safety Tracker
- Replace shelf_cors_headers with custom CORS middleware in server.dart
- Add request_logger middleware with timing for auth and geo routes
- Add REGISTRATION_SECRET_KEY to .env for registration validation
- Remove postgres port exposure from docker-compose.yml
- Update opencode.json model configuration
- Add crypto dependency and update Flutter web assets

web/index.html

@@ -18,6 +18,7 @@
 
   <meta charset="UTF-8">
   <meta content="IE=Edge" http-equiv="X-UA-Compatible">
+  <meta name="referrer" content="strict-origin-when-cross-origin">
   <meta name="description" content="A new Flutter project.">
 
   <!-- iOS meta tags & icons -->