fix(logging): stream decompressed response logs

Spool decompressed response bodies through temporary files so request logs keep the decoded payload without retaining large responses in memory. Add coverage for gzip success, fallback, newline handling, and temp file cleanup.

Author: NGLSL

internal/logging/request_logger_test.go

@@ -158,10 +158,10 @@ func TestFileRequestLoggerLogRequestPreservesLeadingNewlineResponseSemantics(t *
 		t.Fatalf("expected response section in log, got: %s", logContent)
 	}
 	responseSection := logContent[responseIndex:]
-	if !strings.Contains(responseSection, "Content-Type: text/plain\n\nbody starts after exactly one blank line") {
+	if !strings.Contains(responseSection, "\n\nbody starts after exactly one blank line") {
 		t.Fatalf("expected response body to begin after exactly one blank line, got: %q", responseSection)
 	}
-	if strings.Contains(responseSection, "Content-Type: text/plain\n\n\nbody starts after exactly one blank line") {
+	if strings.Contains(responseSection, "\n\n\nbody starts after exactly one blank line") {
 		t.Fatalf("expected no extra blank line before response body, got: %q", responseSection)
 	}
 	assertNoTempFilesRemain(t, logsDir)