fix: more messages say only what is certain

- Host restore notification: reports its tasks and no longer calls the node fully ready.
- Watchdog notification: covers an application that did not start as well as one that stopped again.
- OCI: Modify summary, Immich recognition preview, private network kept by another guest, empty USB list.
- gzip diagnostic no longer says that nothing changed.

Source questions from the Italian review by @f3rs3n.

oci/remote/oci_remove.py

@@ -338,7 +338,7 @@ def remove(root, vmid):
             msg_warn(f"{translate('Could not complete private network release:')} {bridge}")
             incomplete = True
     elif bridge:
-        msg_info(f"{translate('The private network is still used by another container and is kept:')} {bridge}")
+        msg_info(f"{translate('The private network is still used by another guest and is kept:')} {bridge}")
     if not remove_owned_host_firewall(primary):
         incomplete = True
     release_shared_host_files(hookscripts)

oci/remote/oci_watchdog.py

@@ -199,7 +199,7 @@ def look(states, now):
             if started and notice_due(state, now):
                 oci_operation_notice.notify('oci_watchdog_restarted', data)
         elif action == 'give-up':
-            print(f'CT {vmid} ({name}) keeps stopping; it is left stopped', flush=True)
+            print(f'CT {vmid} ({name}) could not be kept running; it is left stopped', flush=True)
             oci_operation_notice.notify('oci_watchdog_failed', data)