refactor: improve responseWriter implementation in proxy transport

[redscholar]

What type of PR is this?

/kind bug

What this PR does / why we need it:

• Updated responseWriter to capture HTTP responses more effectively by using an internal buffer for the response body.
• Modified Header and Write methods to directly manipulate the response object.
• Ensured that the response body is set correctly after processing the request, defaulting to 200 OK if no status code is set.

Which issue(s) this PR fixes:

Fixes #
The reason responseWriter.Write() is called in multiple chunks is that the Go HTTP server flushes data in segments when its internal buffer is full. Even if your handler writes the entire response in one call, the server may split it into multiple writes to the underlying ResponseWriter. io.NopCloser itself does not split the data; the chunked writes come from the server’s internal buffering and flush behavior.

Special notes for reviewers:

Does this PR introduced a user-facing change?

improve responseWriter implementation in proxy transport

Additional documentation, usage docs, etc.:

[kubesphere-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: redscholar

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• OWNERS [redscholar]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[zuoxuesong-worker]

/lgtm