```ts
/**
 * Parses a single CSV line into its fields.
 * Handles quoted fields with embedded commas and escaped quotes.
 * @param line A single line of CSV text.
 * @returns An array of parsed field values.
 */
export function parseCsvLine(line: string): string[] {
  const fields: string[] = [];
  let currentField = '';
  let inQuotes = false;
  let i = 0;

  while (i < line.length) {
    const char = line[i];

    if (!inQuotes) {
      if (char === '"') {
        // Start of a quoted field
        inQuotes = true;
        i++;
      } else if (char === ',') {
        // Field separator
        fields.push(currentField);
        currentField = '';
        i++;
      } else {
        currentField += char;
        i++;
      }
    } else {
      // Inside quotes
      if (char === '"') {
        // Check for escaped quote
        if (i + 1 < line.length && line[i + 1] === '"') {
          // Escaped quote: "" -> "
          currentField += '"';
          i += 2;
        } else {
          // End of quoted field
          inQuotes = false;
          i++;
        }
      } else {
        currentField += char;
        i++;
      }
    }
  }

  // Push the last field
  fields.push(currentField);

  // Check for unclosed quotes
  if (inQuotes) {
    throw new Error('Unterminated quoted field');
  }

  return fields;
}
```