Replace the v2 left column's horizontal tab bar with an always-visible
vertical icon rail. Clicking the active icon collapses the panel (rail
stays); clicking any icon while collapsed reopens it at the persisted
width (clamped to the minimum). Resizer-drag collapse is preserved.
Add an `inspectorFooter` slot to <Editor> (v2), threaded through
PanelManager → ParametricInspector → PanelWrapper, so embedders can dock
an affordance (e.g. "save as preset") below the node inspector.
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
891e578481