* fix(shell): scope volume.fsck filer walk to the bucket when -volumeId selects one bucketed collection
Closes#9345.
-volumeId only filtered which volume .idx files were pulled; the filer-side
BFS still walked from "/", printing every directory under -v and making it
look like the flag was ignored. When all requested volumes share a single
non-empty collection that maps to an existing <bucketsPath>/<collection>
directory, restrict the BFS root to that bucket. Empty-collection volumes
or multi-collection selections fall back to the full walk, since chunks
for those can live anywhere.
* trim comments
* address review: collapse getCollectFilerFilePath; unshadow receiver in loop
b9bf45cb2e