Large Indexing PDF reports now download as a ZIP

Exporting an Indexing report for a site with a very large number of URLs could fail because the PDF was too big to generate. That's fixed.

What changed:

• Reports with up to 500 URLs still download as a single PDF.

• Larger reports now download as a ZIP of numbered PDF parts, each capped at 500 URLs.

Every enabled URL is still included, and the summary totals are unchanged.