refactor: full Python 3.13 idiom pass

- TypeGuard → TypeIs in _code_query.py: TypeIs additionally narrows the False branch (PEP 742), making _is_code_field / _is_code_op more precise - Callable / Iterator imports moved from typing → collections.abc in query_engine.py, _predicate.py, _query.py (canonical source since 3.9) - dataclasses.replace() → copy.replace() in midi_parser.py (PEP 698, Python 3.13 generic form; works on dataclasses, namedtuples, and any class implementing __replace__)

mypy: 0 errors · typing_audit: 0 violations · 1716 tests green