fix(web-ui): menu placement and scrolling, tool-row and settings polish

Menus: keep 12px viewport clearance with internal scroll, pin workspace
create actions in a footer, and pre-render portal lists hidden so the
first painted frame is already at its final position (no open jump).
Tool rows: 14px icons, secondary titles, no hover fill, and a hover
chevron preview on in-place expandable rows. Settings: 800x600 layer-2
panel over a blurred mask, hover states, and wrapping selector cubes;
ModelSelect surface tokens now match the Menu primitive.

packages/client/ui-primitives/src/Tooltip.tsx

@@ -72,7 +72,7 @@ export function Tooltip({ label, side = 'right', disabled = false, children }: {
       {cloneElement(children, {
         ref: mergedRef,
         onMouseEnter: (e) => { children.props.onMouseEnter?.(e); triggers.current.hover = true; show() },
-        onMouseLeave: (e) => { children.props.onMouseLeave?.(e); triggers.current.hover = false; hide() },
+        onMouseLeave: (e) => { children.props.onMouseLeave?.(e); triggers.current.hover = false; setPos(null) },
         onFocus: (e) => { children.props.onFocus?.(e); triggers.current.focus = true; show() },
         onBlur: (e) => { children.props.onBlur?.(e); triggers.current.focus = false; hide() },
       })}