- ThemeBuilderAccess::changeableTemplate(): rights (Q18 not_found), group gate, no TB draft, never the default template, current template_rev - omitted exclude_from stays, [] clears (Q3); live dry run shows use_on and exclude_from before/after, overlaps and possible overlaps (B9) - reattach only with published layouts (B10) and a live TB post; always disabled, unmarks template and layouts; failure restores everything Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>