Phase 6 (final storage phase).
- SidecarRepositoryRegistry tracks every open repo; SidecarFlushObserver
(a WidgetsBindingObserver in main) flushes them all on
inactive/hidden/paused/detached, awaiting each flush — the last
strokes can't be lost on app close, not just on the 800ms timer.
- VaultSearchIndex rebuilds by scanning vault sidecars (the source of
truth) — note titles, OCR text and document names — and search_provider
queries it, so search spans notes + PDFs. Rebuilt on launch / after
import.
The vault file-based storage migration (Phases 0-6) is complete:
annotations travel with the file, picked vault folder, atomic autosave,
one Import-file entry, SQLite migrated to sidecars. analyze clean,
tests green.