chore: release v0.2.4

Merged
TO
2mo ago
+87-63

Bumps the version to 0.2.4 in the five places scripts/check-versions.sh checks and adds the release notes for the tag to publish.


Summary by cubic

Bumps the version to 0.2.4 in the five places scripts/check-versions.sh checks and adds the release notes for the tag. Upgrading to this release changes how scanned-page PDFs behave: conversion now fails with a needsOcr error instead of silently dropping those pages, and an opt-in hosted OCR option is available.