* fix(sandbox): search skills across category mounts
* fix(sandbox): address virtual search mount review
Search explicitly configured category mounts regardless of ignored names,
while retaining descendant filters and host-parent exclusion. Warn with the
virtual mount path before re-raising broken-mount errors, defer ordinary
path resolution, and cover lookahead across mount boundaries.
---------
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
