List: focusable container paints no a11y node (id + track_focus without role) — focus 'disappears' on Tab

[noosxe]

Repro (gpui-component at rev 94a313a, v0.6.0 line; still present at v0.6.6 — list.rs:668-669):

v_flex()
    .key_context("List")
    .id("list-state")
    .track_focus(&self.focus_handle)   // focusable tab stop …
    // … but no `.role(...)` → no accessibility node is painted

List renders a focusable container (track_focus + id) without a role. gpui skips painting the a11y node for roleless focusables (gpui::window::a11y logs: "focused element (FocusId(..)) has no accessibility node (it has an id but no role); assistive technology will announce the whole window instead. Give it both an .id(...) and a .role(...) to expose it.").

Consequences, observed live (headless sway, app with a searchable List in its tab chain):

• Tab reaches the container, and focus "disappears": no node is exposed, so assistive tech announces the whole window.
• set_focus never resolves (nodes.focus stays unset), so any focus reporting built on gpui's a11y debug dump reports gpui_focus: null for that stop.

Suggested fix: paint a role on the container, e.g.

v_flex()
    .key_context("List")
    .id("list-state")
    .track_focus(&self.focus_handle)
    .role(Role::List)          // ← node now exists; focus maps
    ...

(Note Role::GenericContainer is not an option — gpui debug-asserts it is filtered out of the a11y tree.)

Verified downstream that the element is the container (not a child): tab-order position matches the List's paint position, and adding roles to our own root containers removed every other instance of the log line except this one.