[callumalpass]

From live e2e testing of the TaskNotes plugin and app:

• Memoize calendar timezone conversions (2,000-task week projection: ~970 ms → 15 ms).
• Scheduled-to-due span moves shift by civil days and wall-clock time (DST-safe); drops on a day write date-only values.
• Materialized occurrences keep the completed/skipped state the parent records for their date (completedStatus/skippedStatus inputs; missing_skipped_status when none).
• New planCalendarOccurrenceChoice for "this occurrence / whole series" prompts on pattern gestures; buildInheritedOccurrenceTask exported.

Includes the release 0.3.0-rc.19 commit; tag v0.3.0-rc.19 after merge to publish (dist-tag next).