[FR] Add Validation for HTTP Status Code in Speed Test Feature

[yuuuuww]

Feature description

Description:
Currently, the speed test feature in Hiddify only evaluates the loading latency of a URL to determine the fastest proxy server. However, it does not take the actual HTTP status code into account. This can lead to situations where a proxy server with a slow response time is still considered as a viable option, even though the server might return an error status (e.g., 404, 500, etc.), which makes it unusable.

Request:
I would like to propose that the speed test feature should also check for the HTTP response status code. If the status code is an error (e.g., 4xx, 5xx), the result of the speed test should be considered as a "failed route" regardless of the latency. This way, only valid, responsive proxies are considered for automatic switching.

Expected Outcome:

If the response status code indicates an error (e.g., 404, 500, etc.), the proxy server should be marked as unavailable.
The speed test results should reflect both latency and the actual response status, ensuring the best-performing and functional proxy is selected.
Thank you for considering this improvement!

[titancomputer]

PR welcomed