"Read with AI" and the index backfill wrote a text-layer read as a complete
`local-pdf` index although it held only the first ten pages (the render
cap), while the local text index reads up to 200. `prepareVisionInput` takes
the number of pages a text-layer read may take, and both index writers ask
for the local index's own cap, so the index is complete.
The `partial` flag on a text read had no reader and is gone; the
extraction and the lab scan report their missing pages themselves.
Refs #1311
Marc-André Bombeck
253176d01a