Refactor advisor

function addNumbers(firstNumber: number, secondNumber: number): number {
  return firstNumber + secondNumber;
}

• Added number parameter types to fix the implicit any parameters.
• Restricted both operands to numbers, removing ambiguity between numeric addition and string concatenation.
• Added an explicit number return type to document and enforce the function’s contract.
• Renamed add, a, and b to addNumbers, firstNumber, and secondNumber for clearer intent.