BackupEngine: after all retries fail, call fileExists() before recording a
failure. If the file is on NAS (uploaded earlier but fileExists silently
threw on the pre-check), count it as skipped and add it to manifestEntries —
this ensures writeManifest includes every safe asset and prevents alreadySafe
from dropping to 1 after the post-backup reconcile.
BackupView: remove the immediate refreshAndWait from onChange(.failed). That
call raced with refreshAfterBackup's writeManifest, cancelled the manifest-
correct refresh, then reconciled against a stale 1-entry NAS manifest.
Auto-resolve (.failed → .completed when needBackup == 0) is now owned by the
coordinator so it runs after writeManifest finishes.
AutoBackupCoordinator: add backupTriggerArmed flag (set by onActive/
handleNASReachable, cleared by handleReconciliationComplete). Post-backup
reconciles from refreshAfterBackup are no longer able to re-trigger auto-
backup — only an explicit app-open or LAN-join can arm the trigger. Also
added auto-resolve: calls engine.resolveSuccess() when job is .failed but
needBackup == 0, which fires the .completed green-flash path in BackupView.
Co-Authored-By: Kutesir <kutesir@provoc.ug>
Co-Authored-By: Sentry <sentry@provoc.ug>