fix(a11y): touch/keyboard reveal tail + single-Escape layer coordination (UX-7/UX-8)

UX-8: one Escape must close only the topmost layer, never both an open
popover AND the player beneath it. The popover's Escape listener is on
`document` and fires before the player's on `window`; closing the popover
flushes its layer off the shared stack synchronously, so the player's
`anyLayerAbove()` lookup read "nothing above" and closed too. Add a
consumed-event flag to layerStack (`markEscapeHandled`/`escapeHandled`):
the acting topmost layer stamps the shared KeyboardEvent, and both players
check the stamp before the (now-mutated) stack. Immune to listener order
and mid-dispatch stack mutation. Cover with layerStack.dom.test.ts.

UX-7: the E4 `.reveal` sweep already covered the card action rows; two
residual hover-only traps remained — invisible-but-tappable/Tab-focusable
on touch. Add a group-agnostic `.reveal-hover` recipe (display:none under
`(hover: none)`) paired with each site's own hover/focus-within reveal:
- VideoCard play/Continue/Restart overlay: also reveal on
  group-focus-within (keyboard), and drop it on touch — the card tap
  already plays/resumes, so no permanent scrim over every mobile thumbnail.
- Carousel prev/next arrows: gone on touch, where the strip swipes.

frontend/src/components/PlexPlayer.tsx

@@ -53,7 +53,7 @@ import { LS, useAccountPersistedObject } from "../lib/storage";
 import { useDismiss } from "../lib/useDismiss";
 import { useScrollFade } from "../lib/useScrollFade";
 import { useBackToClose } from "../lib/history";
-import { pushLayer, removeLayer, anyLayerAbove } from "../lib/layerStack";
+import { pushLayer, removeLayer, anyLayerAbove, escapeHandled } from "../lib/layerStack";
 
 // The rich info overlay (poster/cast/ratings) reuses the same component as the card's info page.
 const PlexInfo = lazy(() => import("./PlexInfo"));
@@ -602,7 +602,10 @@ export default function PlexPlayer({ itemId, onClose, queue }: Props) {
         case "Escape":
           // Defer to any layer opened above the player (Modal or anchored popover) — let it take the
           // Escape, not us. A player MENU registers as a layer too, so it closes first and the next
-          // Escape reaches the auto-skip-cancel below (the old blanket-stopPropagation bug).
+          // Escape reaches the auto-skip-cancel below (the old blanket-stopPropagation bug). Check the
+          // consumed-event flag first (UX-8): a layer's `document` listener runs before this `window`
+          // one and its close can pop it off the stack synchronously, so `anyLayerAbove` alone misses it.
+          if (escapeHandled(e)) break;
           if (layerIdRef.current != null && anyLayerAbove(layerIdRef.current)) break;
           if (skipProgressRef.current != null) cancelAutoSkipRef.current();
           else if (menuOpenRef.current) {