formatHeadersForCopy static method
Formats headers for clipboard paste into tools like Postman (bulk edit).
One Key: Value entry per line; list values are joined with , .
Implementation
static String formatHeadersForCopy(Map<String, dynamic> headers) {
if (headers.isEmpty) return '';
return headers.entries
.map((e) => '${e.key}: ${_stringifyHeaderValue(e.value)}')
.join('\n');
}