Fix parent job sync when parent reaches 100% progress (#6282)

* Fix parent job sync when parent reaches 100% progress

When a child job completes and syncs its progress to a parent job,
it can set the parent to 100% progress. However, there are situations
where a second child job for the same parent job is created after the
parent has already reached 100%. This caused a ValueError when creating
a ParentJobSync for subsequent child jobs, as the validator required
starting_progress < 100.0.

This issue was introduced in #6207 (shipped in 2025.10.0) but only
became visible in 2025.10.1 with #6195, which started using progress
syncs. The bug manifests during Core update rollbacks when a second
docker_interface_install job is created after the parent already
reached 100% from the first install.

Fix by skipping parent job sync setup when the parent is already done
or at 100% progress, as there's no value in syncing progress to a
completed parent.

* Update comment and add debug message

supervisor/jobs/__init__.py

@@ -327,6 +327,17 @@ class JobManager(FileConfiguration, CoreSysAttributes):
                 if not curr_parent.child_job_syncs:
                     continue
 
+                # HACK: If parent trigger the same child job, we just skip this second
+                # sync. Maybe it would be better to have this reflected in the job stage
+                # and reset progress to 0 instead? There is no support for such stage
+                # information on Core update entities today though.
+                if curr_parent.done is True or curr_parent.progress >= 100:
+                    _LOGGER.debug(
+                        "Skipping parent job sync for done parent job %s",
+                        curr_parent.name,
+                    )
+                    continue
+
                 # Break after first match at each parent as it doesn't make sense
                 # to match twice. But it could match multiple parents
                 for sync in curr_parent.child_job_syncs: