[iskandr]

Valid expression CSV tables with a header and one patient measurement were parsed as TSV because delimiter inference required three lines. Infer from the available informative lines instead; skip comments and blank lines, and retain an explicit error for files without any header/data lines. Header-only tables work with declared value columns; inferred numeric columns still require measurements.

Both file and CLI-spec loaders run the same CSV/TSV battery with zero, one and multiple rows. A composed regression loads one expression feature, joins it to predictions, changes selection with abundance, and saves/replays the selection decision. Bumps Topiary 5.94.2 to 5.94.3.

Fixes #486. Unblocks openvax/vaxrank#585 without a consumer-specific delimiter workaround.

Validation: ./lint.sh passed; 17 focused regressions passed; the complete ./test.sh passed 5,469 tests with 20 optional skips in 709.91 seconds. All exact-head GitHub CI checks passed, including Python/pandas matrices and Isovar/PirlyGenes integration. Local HTTP retry tests required localhost networking outside the sandbox.

The full gate also exposed high-depth RNA support-processing cost in an existing mitochondrial fixture; recorded separately at openvax/isovar#463. No Isovar behavior, read limits or consumer workaround changed in this PR.

[coveralls]

coverage: 93.527% (+0.2%) from 93.289% — fix/486-short-expression-tables into master