Please address the comments from this code review:
## Overall Comments
- In the unexpected error branch, pass the error object as a separate argument to logger.error (e.g. logger.error('testProxy error: unexpected error', error)) or JSON.stringify it to capture the full stack trace instead of string concatenation.
- Add a separator (e.g. ': ') before concatenating the error to improve log readability (currently it produces 'unexpected error[object Object]').
- The extra error.message check in the second branch is redundant since all AxiosError instances include a message—consider simplifying that condition to just axios.isAxiosError(error).

## Individual Comments

### Comment 1
<location> `src/api/controllers/proxy.controller.ts:63` </location>
<code_context>
+        logger.error('testProxy error: ' + error.message);
       } else {
-        logger.error('testProxy error: ');
+        logger.error('testProxy error: unexpected error' + error);
       }
       return false;
</code_context>

<issue_to_address>
String concatenation with an Error object may not yield useful output.

Instead of concatenating the error object, pass it as a separate argument to logger.error to retain full error details.
</issue_to_address>

Please address the comments from this code review:
## Overall Comments
- Consider logging the error.stack alongside the message to provide better debugging context when tracing issues.
- Rather than JSON.stringify(error), pass the error object directly to the logger or use util.inspect to capture non-enumerable properties and avoid missing details.
- Verify that logging error.response.data won’t expose any sensitive information—scrub or truncate if necessary before writing to the logs.

Please address the comments from this code review:
## Overall Comments
- Consider including error.response.data alongside error.message when logging Axios errors so you don’t lose potentially important server response details.
- For unexpected errors, pass the actual error object into logger.error rather than concatenating it to a string to preserve the full stack trace and context.