fix(media): a sweep carries the emptied folder's own empty subfolders

The live sweep removed 2271 husks and left 146 standing, every one a release
folder blocked by a junk subfolder (Screens/, Sample/, a BDMV leaf) that no
file ever moved out of. Eligibility was per-folder, so the blocker was never a
target and its parent could never be removed.

Proof now carries downward: inside a folder the journal shows emptied, every
empty directory qualifies. Nothing under such a folder can hold data, and every
removal is still journalled as rmdir and undone by rollback.

The new test is red against the previous revision, green now. The live sweep
touched no file: 8193 before, 8193 after.

serverAppConfigs-docs/Dankserver/Media Relayout.md

@@ -155,6 +155,10 @@ curl -s -K /tmp/jf.hdr -o /dev/null -w "jellyfin scan: %{http_code}\n" \
   inside disqualifies the subtree, because the thing behind a link is not this
   tool's to delete. Every removal is journalled as `rmdir` and `rollback`
   recreates the folder, so the sweep is undone by the same command as the moves.
+  Proof carries downward: inside a folder the journal proves emptied, every
+  empty directory goes with it. A release's `Screens/` or `Sample/` is never a
+  move source itself, so 146 of them held their emptied parents on disk after
+  the first sweep.
 - **An episode-shaped name marks a SERIES, not a film — and the series is the
   name BEFORE the marker.** `Monk - S05E03 - Mr. Monk and the Big Game` is series
   `Monk`. Keyed on the whole title instead, every episode became a group of one