Save only lens parameters on existing CPU/GPU jobs while keeping unrelated
draft settings dirty. Retain pinned checkpoints through preview and status,
and release host-only snapshots outside the status lock.
Use the admitted PNG bound for registered-executor checkpoint slots. Preserve
executor work credits, final publication and regrade ownership. Add regression
coverage and align help, translations and capability documentation.
* claim: #6281
* docs: record the Render workspace interaction design and implementation roadmap
* docs: plan the Render panels so each has one purpose
* docs: replace the tabs-and-ribbon plan with the stage-bar design
* docs: drop the note about the superseded draft
* docs: plan every Render panel and where each old control goes
* docs: defer the shared lighting rig, UI steps go first