chore: bump version to 0.5.2, update README and changelog

docs: update README and updater.md for v0.5.1 release

chore: update vendor/composer with production autoloader (no PHPStan)

fix: merge migrate_0.5.0.sql into migrate_0.4.9.9.sql

version_compare('0.5.0', '0.4.9.9', '<=') is FALSE in PHP,
so migrate_0.5.0.sql would never execute when upgrading to 0.4.9.9.
Merged its contents (sharing settings, plugin_hooks unique index)
into migrate_0.4.9.9.sql. All statements are idempotent.

docs: update README changelog and badge for v0.4.9.8

chore: bump version to 0.4.9.7

chore: make create-release.sh executable

chore: bump version to 0.4.9.4 and update changelog

- Update version.json to 0.4.9.4
- Add v0.4.9.4 changelog: audiobook player, Z39.50/SRU plugin,
  global keyboard shortcuts, scroll-to-top, security hardening
- Move v0.4.9.2 changelog to Previous Releases section
- Update version badge

chore: bump version to 0.4.9.2

chore: update vendor/composer with production autoloader (no PHPStan)