[Feature] Mobile: show when a large upload was interrupted instead of restarting it silently

I have searched the existing feature requests, both open and closed, to make sure this is not a duplicate request. • Yes The feature Make it visible in the mobile app when a foreground upload was cancelled and restarted, instead of retrying silently. Background. When the app leaves the foreground (screen off, switching apps) during a foreground upload, the in-flight POST /assets is cancelled and starts again from 0 % when the app is resumed. According to #32422 and #29005 this is by design, and resumable/chunked uploads are already tracked in #1674 and #22385. This request is about neither of those. The problem is that the user is never told. For a large video (several GB), what happens today is: • the upload is cancelled and restarted from zero, again and again, with no message • the asset simply stays "not backed up"; nothing shows that it was attempted, how far it got, or why it was dropped • the only way to find the cause is the reverse prox…