Removed a needless “changes weren’t saved” notice and made trash auto-cleanup safer

Sometimes a “Some changes weren’t saved” notice appeared even though nothing was lost. It came from this device trying to clean up trash items another device had already emptied — your data was never affected.

• That notice no longer appears. If saving ever does fail, we see it on our side first and fix it
• The 30-day trash auto-cleanup now runs only after this device has finished syncing with the server
• The message shown when sync stops has been simplified — it now just tells you your edits are safe on this device
• (Android) The same changes ship with the next app update
• Plus general stability improvements