isDefinitelyText static method
Checks if buffer looks definitely like text (not JSON)
Implementation
static bool isDefinitelyText(String buffer) {
final clean = buffer.trim();
// Need at least 5 characters to be confident
if (clean.length < 5) return false;
// If it starts with JSON indicators, it's not text
if (isJsonStart(buffer)) return false;
// If no JSON patterns in first 30 chars, it's text
final early = clean.length > 30 ? clean.substring(0, 30) : clean;
return !early.contains('{') && !early.toLowerCase().contains('json') && !early.contains('<tool');
}