v1.1

Offline Caching

Add offline caching for task creation, viewing, and completion
Tasks created via Quick Entry are now cached to disk when the API call
fails due to network errors, and automatically synced when connectivity
returns. Quick View caches the last fetched task list and serves it when
offline, with a status bar showing cache age. Task completions and undos
are also queued offline with intelligent cancellation (undo cancels a
pending complete instead of creating a separate action).

The cache persists across app crashes and reboots via an atomic
write-ahead file (offline-cache.json). A 30-second background sync timer
plus opportunistic sync on window show ensures pending actions are
flushed promptly. Auth errors pause sync without discarding actions;
permanent errors (404) are discarded; server errors are retried.