Preserve request body in debug output for all methods

[bkiran6398]

🔧 Changes

Fixes DebugTransport to preserve request bodies in debug log output for POST, PATCH, and PUT requests.

Previously, DebugTransport called dumpRequest after base.RoundTrip() to capture headers set by inner transports. However, RoundTrip consumes the request body stream, so httputil.DumpRequestOut found an empty body — making debug logs useless for any request with a payload.

• Buffers the request body before RoundTrip and restores it afterward for dumping
• GET requests and error paths continue to work correctly

📚 References

🔬 Testing

Added 5 new unit tests to TestDebugTransport:

• POST body preserved — mock transport consumes body, asserts body appears in log
• PATCH body preserved — same pattern for PATCH method
• PUT body preserved — same pattern for PUT method
• Body preserved on error — verifies body is logged even when transport returns an error
• GET with no body — confirms nil-body path is unaffected

Run tests:

go test ./internal/client/ -run TestDebugTransport -v

📝 Checklist

• All new/changed/fixed functionality is covered by tests (or N/A)
• I have added documentation for all new/changed functionality (or N/A)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.25%. Comparing base (ceabda7) to head (3bae315).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #751   +/-   ##
=======================================
  Coverage   87.25%   87.25%           
=======================================
  Files         350      350           
  Lines      139272   139278    +6     
=======================================
+ Hits       121519   121525    +6     
  Misses      13219    13219           
  Partials     4534     4534           

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[developerkunal]

A couple of small suggestions for the body-buffering block:

1. The original req.Body is never explicitly closed after ReadAll. It would be good to call req.Body.Close() before replacing it.

2. The error from io.ReadAll is silently discarded. If reading fails partway through, a truncated body would be sent to the server without the caller knowing. In practice this is unlikely since bodies are typically bytes.Reader or strings.Reader, but it's still worth handling.

Something like:

var bodyBytes []byte
if req.Body != nil {
    bodyBytes, err := io.ReadAll(req.Body)
    req.Body.Close()
    if err != nil {
        return nil, fmt.Errorf("debug transport: failed to read request body: %w", err)
    }
    req.Body = io.NopCloser(bytes.NewReader(bodyBytes))
}

Otherwise the fix and tests look good!