Render a template before it is published

The template's own canvas plus its baked plan and specs — the same payload the editor reads, so the panel renders a draft with the same code it renders a live one.

This exists because a draft had no readable board anywhere. The row's preview_token is the source dashboard's PUBLIC share url and is null until it is published, and the by-id editor read is gated on per-dashboard workspace access, which a curated-grant operator who did not run the import does not have. So the only way to see a template was to publish it — which is the same action that puts it in front of every customer. Reviewing before shipping is the entire point of a draft, and it was the one thing a draft could not do.

Static, no data, and no workspace: same gate as this panel's data preview, which is identity plus curated-only. Live rows are served too — one door, so the panel does not branch on state.