Reject a truncated iNES header instead of parsing past its end

[arpitjain099]

parse_ines_header checks the magic and then reads header[4] through header[10] and slices header[11:], but parse_ines gets the header from file_stream.read(16), which returns short on a truncated file. Only the magic is validated, so a 4 byte file gets through.

On a ROM cut to 4 bytes, polyfile --format json logs Parser parse_ines ... raised an exception while parsing: index out of range, exits 0, and still emits an iNESHeader element with "size": 16 for a 4 byte file, with everything after the magic missing. A consumer of that JSON sees a partial structure and a length that cannot be right.

Lengths 11 to 15 are worse in a way, since nothing raises at all: header[11:] just returns short, so the output carries a 16 byte iNESHeader and an undersized UnusedPadding with no warning anywhere.

Raising InvalidMatch matches how the bad-magic case is already handled, and the dispatcher treats it as a clean non-match rather than an internal error. A well-formed ROM is unaffected, and I confirmed the full structure still comes out for one.

The new tests cover lengths 4 to 15; all twelve fail on master. tests/unit is 81 passing.