- TestRetryProcessingIssueRowless: a row-less import_failed entry retries
to a real import and resolves; a missing file retries to 409 with the
real reason and stays open; an item-backed issue retries through the
rescan mechanism and resolves.
- TestScanLibraryFolderPathValidation: an unregistered folder_path is a
400; a registered one scopes and enqueues (202).
- TestScanSingleFolderSkipsArchiveReconciliation: scanning one folder of
a two-folder library leaves the other folder's healthy item at
missing_scan_count 0 / unarchived — pinning the partial-scope guard
against the false-archive regression it exists to prevent.
