refactor(utils): Extract utilities from server.js

- Create src/utils/http.js - fetchT and HTTP helpers
- Create src/utils/logging.js - Structured logging and error logging
- Create src/utils/responses.js - Standard API responses
- Create src/utils/async-handler.js - Async wrapper with error handling
- Create src/utils/index.js - Consolidated exports

Removes scattered helper functions from server.js

dashcaddy-api/src/utils/responses.js

@@ -0,0 +1,22 @@
+/**
+ * Response helpers - Standard API response formats
+ */
+
+/**
+ * Standard error response
+ */
+function errorResponse(res, statusCode, message, extras = {}) {
+  return res.status(statusCode).json({ success: false, error: message, ...extras });
+}
+
+/**
+ * Standard success response
+ */
+function ok(res, data = {}) {
+  return res.json({ success: true, ...data });
+}
+
+module.exports = {
+  errorResponse,
+  ok,
+};