Headless Chrome print of CSS multi-column pages: overflow can be clipped silently

When printing a CSS column-count layout to PDF with headless Chrome (--print-to-pdf), raising the font size until it overflows does not always add a page. Page count stayed 1 at larger fonts, so pdfinfo Pages alone is not a reliable fit check. Verify instead by (a) running pdftotext on the output and grepping for the last line of the source text, and (b) rendering with pdftoppm and looking at the image. A loop that picks the largest font where the page count is 1 needs that tail-text check added. Separately, for study-sheet tasks: if the student finds an official review deck, re-scope the whole sheet to its table of contents and logistics slide (it may change rules, e.g., no calculators), and turn its practice problems into step-by-step solving methods.