[log] Add debug logging to response_writer.go (#636)

## Changes

Enhanced the `internal/server/response_writer.go` file with debug
logging to improve troubleshooting capabilities for HTTP response
handling.

### What was added:

1. **Logger declaration**: Added `logResponseWriter` with namespace
`server:response_writer` following project conventions
2. **Response writer creation**: Logs when a new response writer is
created
3. **Status code tracking**: Logs when HTTP status codes are set
4. **Body writes**: Logs the size of response body writes
5. **Data retrieval**: Logs when body content or status codes are
retrieved

### Benefits:

- Better visibility into HTTP response flow
- Helps debug response-related issues
- Follows the project's logger naming convention (`pkg:filename`)
- No side effects in logger arguments
- Minimal performance impact (logging only when DEBUG is enabled)

### Testing:

The changes follow Go best practices and the project's logging
guidelines from AGENTS.md. To see the debug output:

``````bash
DEBUG=server:response_writer ./awmg --config config.toml
``````

Or enable all server logs:

``````bash
DEBUG=server:* ./awmg --config config.toml
``````

### Quality checklist:

- ✅ Single file modified (focused PR)
- ✅ No test files modified
- ✅ Logger follows `pkg:filename` naming convention
- ✅ Logger arguments have no side effects
- ✅ Meaningful and helpful logging messages
- ✅ No duplicate logging
- ✅ Imports properly formatted


> AI generated by [Go Logger
Enhancement](https://github.com/github/gh-aw-mcpg/actions/runs/21678050763)

<!-- gh-aw-workflow-id: go-logger -->

Author: lpcox

internal/server/response_writer.go

@@ -3,8 +3,12 @@ package server
 import (
 	"bytes"
 	"net/http"
+
+	"github.com/github/gh-aw-mcpg/internal/logger"
 )
 
+var logResponseWriter = logger.New("server:response_writer")
+
 // responseWriter wraps http.ResponseWriter to capture response body and status code
 // This unified implementation replaces loggingResponseWriter and sdkLoggingResponseWriter
 type responseWriter struct {
@@ -15,28 +19,34 @@ type responseWriter struct {
 
 // newResponseWriter creates a new responseWriter with default status code
 func newResponseWriter(w http.ResponseWriter) *responseWriter {
+	logResponseWriter.Print("Creating new response writer with default status 200")
 	return &responseWriter{
 		ResponseWriter: w,
 		statusCode:     http.StatusOK,
 	}
 }
 
 func (w *responseWriter) WriteHeader(statusCode int) {
+	logResponseWriter.Printf("Setting response status code: %d", statusCode)
 	w.statusCode = statusCode
 	w.ResponseWriter.WriteHeader(statusCode)
 }
 
 func (w *responseWriter) Write(b []byte) (int, error) {
+	logResponseWriter.Printf("Writing response body: %d bytes", len(b))
 	w.body.Write(b)
 	return w.ResponseWriter.Write(b)
 }
 
 // Body returns the captured response body as bytes
 func (w *responseWriter) Body() []byte {
-	return w.body.Bytes()
+	bodyBytes := w.body.Bytes()
+	logResponseWriter.Printf("Retrieving captured body: %d bytes", len(bodyBytes))
+	return bodyBytes
 }
 
 // StatusCode returns the captured HTTP status code
 func (w *responseWriter) StatusCode() int {
+	logResponseWriter.Printf("Retrieving captured status code: %d", w.statusCode)
 	return w.statusCode
 }