Signed-off-by: boojack <stevenlgtm@gmail.com>

Close long-lived SSE streams before HTTP shutdown so graceful shutdown is not held until the deadline. Also wait for background runners before closing the store to make shutdown ordering explicit.

Signed-off-by: Mattia Borda <mattiagiovanni.borda@icloud.com>

Co-authored-by: memoclaw <265580040+memoclaw@users.noreply.github.com>

Co-authored-by: memoclaw <265580040+memoclaw@users.noreply.github.com>

Signed-off-by: Takuro Onoue <kusanaginoturugi@gmail.com>

Gate auto-save on initialization to prevent empty content from overwriting
cached drafts on remount. Flush drafts synchronously on visibilitychange/
pagehide so Chromium tab suspension cannot drop pending debounced saves.
Restore cached draft over saved memo content when they differ (inline editing).