Editing continues without a connection and merges conflict-free on
reconnect (ADR 0003, realtime-collaboration.md §Offline).
- y-indexeddb mirrors every opened page's Y.Doc to IndexedDB, sharing the
document with the collab provider. The local copy is discarded when the
page is left after a successful server sync (bounding IndexedDB growth)
and kept otherwise so offline edits survive to the next visit.
- vite-plugin-pwa service worker precaches the app shell (build assets only)
with a navigation fallback; `/api` and `/collab` are denylisted and there
is no runtime caching, so API responses are never cached or poisoned.
- Offline page resolution WITHOUT caching API responses: the app itself
persists the small metadata it needs to reopen a visited page (page/pond
ids + slugs, bounded LRU in localStorage) and the last signed-in user, so
after an offline tab reload the app stays signed in, resolves the page, and
restores its content from IndexedDB. Both are revalidated when the network
returns (a 401 clears the cached user).
- Local-only UI: a banner when there are edits held only on this device
(provider `onUnsyncedChanges`), de + en.
Tests: `page-cache` unit test (remember/recall + bounded eviction); a new
`offline` e2e pack (validated locally against the full stack and wired into
CI): edit, reload while offline (shell from the SW, content from IndexedDB),
assert an API call fails offline (no SW API caching), then reconnect and a
second client converges. The e2e static server serves `.webmanifest`.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PGdhRiwU1WRL4XxJfZYipY
