surface_input has no pointer enter/leave, so a producer cannot clear hover state #5

Crate: gpui_interop 0.1.3 and 0.2.0 (src/input.rs).

The gateway reports moves, downs and ups; nothing tells a producer that the pointer left the surface. A viewport that highlights on hover (a gizmo handle, a navigation-cube face, a cursor hint) cannot clear that state except by guessing from a move's position — and on leave there may be no further move inside the surface at all.

GPUI already has the transition: on_hover(|hovered: &bool, ..) (bite-gp-authoring/src/elements/div.rs:1661), which fires on both edges.

Suggested:

SurfaceEvent::PointerEnter { modifiers: SurfaceModifiers },
SurfaceEvent::PointerLeave { modifiers: SurfaceModifiers },

delivered from an on_hover listener registered in attach() alongside the pointer ones. No position: the event says the pointer came or went, not where it is.

We carry this in a vendored copy.

Status (0.2.0, 2026-11-03): unchanged — src/input.rs is byte-identical
between 0.1.3 and 0.2.0, and the patch described here still applies
unchanged.