Assert-IsoStructure.ps1 reused a fixed mount dir; a prior aborted run left a WIM
mounted there, so Mount-WindowsImage failed with 'directory is not empty' and the
persist-to-stable-path step was skipped (no ISO deployed). Now discards stale mounts
+ clears corrupt mount points + uses a unique per-run mount dir (mirrors build.ps1
Stage 0), and removes the dir after. Also asserts apps/catalog.json baked into the WIM.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>