Patch release bundling the fixes for #34 (pre-1970 recurring events could
not be opened) and #27 (time-picker dial ignored the 24h setting), plus
#30 (create events from external ACTION_INSERT launches). Bumps
versionName to 2.13.1 (versionCode 21301) and cuts the changelog.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
