fix: complete logic audit — mark_completed on transfer, reset_state for interactive source, proper error propagation, user-visible commands

source/source.py

@@ -329,9 +329,10 @@ def do_transfer_offer():
     key_path = None
     try:
         key_path = pick_or_setup_ssh_key(host, user, port_int)
-    except RuntimeError:
-        # pick_or_setup уже дал инструкции, останавливаемся
-        return
+    except RuntimeError as exc:
+        # pick_or_setup уже дал инструкции, помечаем ошибку и выходим
+        state.set_error("ssh_key_setup", "", str(exc), suggestion="Настройте SSH-ключ и запустите: docker-migrate --resume")
+        raise
 
     if key_path:
         state.set_stage("TRANSFER", target_host=host, target_user=user, target_port=port_int, ssh_key=key_path)