fix(lcms): stop plain MS jcamp from being detected as Chemstation LC/MS - #322

A plain chem-spectra-generated MS export carries a MASS SPECTRUM root
DATA TYPE that isChemstationLcms mistook for a genuine Chemstation
LC/MS file. Bail out early on signatures unique to the plain export
(SPECTRUM category, ##$CSSCANAUTOTARGET, the M/Z units triplet, or
##NTUPLES = MASS SPECTRUM), and tighten the remaining heuristic to
require TIC/UVVIS category or multi-page metadata.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

…veto

The prior fix's early-return blacklist (SPECTRUM category, ##$CSSCANAUTOTARGET,
##NTUPLES=MASS SPECTRUM) ran before all positive LC/MS evidence, so it could
override a genuine Chemstation export, and it relied on $CSCATEGORY parsing
that silently dropped single (non-array) values. Its added
(hasMultipleSpectra && hasPageMetadata) clause was also self-defeating: the
original plain-MS fixture has multi-page structure too, so that clause alone
reclassified it as LC/MS again.

Fix the array-vs-string $CSCATEGORY read, drop the blanket blacklist, and
narrow the veto to the one genuinely ambiguous case (multi-page MASS SPECTRUM
root with no other chromatographic hint), gated only on the MS-specific units
triplet and placed after all positive-evidence branches so it can never
override them.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>