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

bin/middleware/request_logger.dart

@@ -0,0 +1,26 @@
+void logRequest({
+  required String method,
+  required String url,
+  required int status,
+  required Duration duration,
+  DateTime? startTime,
+  String? body,
+  Map<String, String>? responseHeaders,
+}) {
+  final start = startTime ?? DateTime.now();
+  final timestamp = start.toIso8601String();
+  final durationMs = duration.inMilliseconds;
+  final bodyPreview = body != null && body.length > 500 ? '${body.substring(0, 500)}...' : body;
+
+  print('[$timestamp] $method $url -> $status (${durationMs}ms)');
+  if (bodyPreview != null && bodyPreview.isNotEmpty) {
+    print('  Body: $bodyPreview');
+  }
+  if (responseHeaders != null) {
+    final contentType = responseHeaders['content-type'];
+    if (contentType != null) {
+      print('  Content-Type: $contentType');
+    }
+  }
+  print('');
+}