Add overlay components 176-195; pixel Harbor and Kit.Cue

Dialogs on DialogBase with focusable panels that harbor parked focus,
popovers on PopoverBase, bubbles, drawers, sheets, a lightbox, an RPG
dialogue box, notifications, a pause menu and a dithered title card.
Kit.Cue moves from feedback to pixel.

AGENTS.md

@@ -56,12 +56,12 @@ Imports point down only. Same-tier imports are forbidden. `internal/archtest` en
 - Signatures and results: PRD §5.1. Zero options give the default look. Sizes in options are dots.
 - `k := pixel.K(c)` once per component; layout sizes through `k.D(n)`. Integer options default through `pixel.Or`.
 - Custom-drawn controls end their Draw with `g.Finish(st)`. Grids of cells moved by arrows use `pixel.Pad`; one-shot timing steps with `k.Since`.
-- A one-shot effect inside a lasting view starts when its cue changes (a `Cue` option, or a value that rises), never on its first frame. A state screen (`ErrorState`, `SuccessState`) starts when it appears. Decorative motion jumps to its end under Reduce Motion; countdowns and loaders keep time.
+- A one-shot effect inside a lasting view starts when its cue changes (a `Cue` option read through `k.Cue`, or a value that rises), never on its first frame. A state screen (`ErrorState`, `SuccessState`) starts when it appears. Decorative motion jumps to its end under Reduce Motion; countdowns and loaders keep time.
 - Containers take content as a final `func()`; interactive results are `NameResult`.
-- A Clicked, Shortcut, Changed or drag during the build makes MyGo build the frame again, so what they change shows at once. State changed any other way after its element was built (`Pressed`, `Edit.Changed`) is read at paint time.
+- A Clicked, Shortcut, Changed or drag during the build makes MyGo build the frame again, so what they change shows at once. State changed any other way after its element was built (`Pressed`, `Edit.Changed`, a drag's release) is read at paint time, or set on the element after its children.
 - Never call `Selected`. The pixel theme keeps MyGo's row highlights clear, since scrolled rows sit between dots: draw chosen rows yourself.
 - A disabled or inert scroll view must not move: cover it, so the wheel stops above it.
-- A press focuses the nearest focusable element under it, or nothing; a closing overlay hands the focus back to its opener. While a press is on, `Hovered` is false for every other element: ask `Pressed`.
+- A press focuses the nearest focusable element under it, or nothing, and a focusable element keeps the click: clicks never reach its ancestors. A control that acts on a press is that focusable element. A `DialogBase` moves the focus inside as it opens and keeps Tab there, but only onto something focusable: make its panel focusable, ring off, and build its children in `pixel.Harbor(c, panel, …)` so controls turning off park their focus there and get it back. A closing overlay hands the focus back to its opener. While a press is on, `Hovered` is false for every other element: ask `Pressed`.
 - Enter and Space click a focused clickable element unless a `Shortcut` takes them. Take them wherever a click reads the pointer's position.
 - Under `pixel.Settings.Inert` (a busy veil) `pixel.Shell` disables every base and gives the focus back after. A popup sits above any veil: a control closes its popup when disabled or inert.
 - Elements are known by their place among siblings. Wrap one whose earlier siblings come and go in `ui.Box(c).Key(k)`, or it loses focus and state.