Kit · K02: Tab binds under FocusScope's ElyFocus context, so a deeper context's Tab wins

AGENTS.md

@@ -54,7 +54,7 @@ Ely GPUI Component. A component library for GPUI, in light and dark.
 - `svg()` paints only with its own `text_color`. `Icon` always sets one.
 - Buttons stay out of focus on click (`prevent_default` on mouse down). Tab still reaches them.
 - The focus ring is a 1px focus-colored border (`FocusRing`). gpui paints shadows under the element, so a shadow ring floods transparent elements. Focusable elements keep a 1px border, transparent at rest.
-- `ely_gpui_component::init` binds Tab and Shift-Tab to `FocusNext` and `FocusPrev`. Wrap the root in `FocusScope` with `.root()` and focus its handle. A root scope takes focus when the focused element leaves the tree, as a toast's or an alert's button does.
+- `ely_gpui_component::init` binds Tab and Shift-Tab to `FocusNext` and `FocusPrev` under `ElyFocus`, the key context every `FocusScope` sets. gpui ranks a binding with no context at the deepest level, so a host's Tab in a deeper context, GPUI Kit's code editor among them, lost or won by which `init` ran last; under a context, the deeper one wins. Wrap the root in `FocusScope` with `.root()` and focus its handle. A root scope takes focus when the focused element leaves the tree, as a toast's or an alert's button does.
 - The gallery scripts mouse input by posting `NSEvent`s to its own queue, so a press takes AppKit's path and reaches a native view over the window (`misc::WebView`). `Window::dispatch_event` reaches only gpui's listeners. gpui's normal window takes mouse moves from a tracking area, which only a real cursor feeds, so the harness sets the window's `acceptsMouseMovedEvents` for posted moves.
 - gpui starts a drag on the first move past its threshold, and only the moves after it reach `on_drag_move`. gpui 0.2.2's mac window replayed a held drag every 16 ms; gpui_macos replays only while `pressedMouseButtons` shows a real button, which posted events never set. So `Step::DragTo` posts each move twice, as the replay did: the second post of the first step reaches `on_drag_move`, where a component that anchors on its first drag move sets its anchor (Scrollbar, Knob, Split).
 - Every shot of a gpui window, a page's or a script's, waits three of its frames through `on_next_frame`: gpui presents without waiting on the GPU, and a heavy page's draw outlasts a fixed pause, so a shot could show the frame before the last step. A page's pauses stay, for work off the main thread such as pictures decoding. A covered window draws no frames, so its capture fails after 5 s instead of shooting a stale frame.