```ts
/**
 * Splits a CSV line into its fields on commas, handling quoted fields with embedded commas and literal quotes.
 * @param line - The CSV line to split.
 * @returns An array of field values.
 */
export function parseCsvLine(line: string): string[] {
  const result: string[] = [];
  let field = '';
  let inQuote = false;

  for (let i = 0; i < line.length; i++) {
    if (line[i] === '"') {
      if (i > 0 && line[i - 1] !== '\\') {
        inQuote = !inQuote;
      }
    } else if (line[i] === ',' && !inQuote) {
      result.push(field.trim());
      field = '';
    } else {
      field += line[i];
    }

    // Check for unclosed quote
    if (i === line.length - 1 && inQuote) {
      throw new Error('Quoted field is never closed');
    }
  }

  result.push(field.trim());
  return result;
}
```