- Parse // comments in parse_statement by consuming tokens until newline
- Add NODE_NOP for no-op statements (comments)
- Support grouped expressions with parentheses in parse_term
- Parse function calls in parse_term() so they work inside expressions
(e.g. z = len(x), y = len(x) + 1)
- Add len() built-in for string length in evaluator
- Add NODE_CALL with name, args, and arg_count to parser
- Add TOK_COMMA token and tokenize (, ), , in lexer
- Remove TOK_PRINT/TOK_PRINTLN keywords; print/println are now regular
identifiers resolved as built-in functions in the evaluator
- Add NODE_CALL debug output in ast_print
