First slice of offline-first (Phase 1). Makes every dashboard area *viewable*
offline with last-synced data, instead of empty lists on an offline reload
(previously only next-pwa's 10-min API cache survived).
- offline-db: add a generic `kv` IndexedDB store (DB v2, preserves order_queue)
with kvGet/kvSet/kvDelete; all degrade silently on quota/unavailable.
- query-persister: debounced snapshot of the React Query cache via
dehydrate/hydrate (no new dependency). Restore is guarded by a schema buster,
24h max-age, and a café scope so one tenant never hydrates another's data.
- providers: gcTime 24h so hydrated data isn't GC'd; restore on mount + persist
on cache changes, re-scoped when the signed-in café changes.
No write-path changes; the existing POS order queue is untouched. Next in
Phase 1: generalize that queue into an idempotent outbox with client→server
ID remapping.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
soroush.asadi
132f0921e0