fix(keys): epic-end review round 1 — Back, menus and dialogs keep the focus where it belongs

Deep-review of E11 (19 raised, 14 confirmed; 2 refuted, 3 latent test-hardening notes dropped).

- Back from a sub-view (a Plex show page, a Messages thread) restores the item it was opened from
  even when focus was still inside the view: the first attempt now waits one task, past the
  sub-view's own popstate listener (measured in Chrome: it left focus on <body>).
- The restore listener is installed at load, so the first Back after a reload finds it; a push
  cancels a restore still waiting for the last landing's lists.
- Navigating over an overlay asks it again, a render apart, while its entry stays: the Plex
  player peels one panel per Back step, so Shift+W over info + stats closed one panel and dropped
  the navigation.
- j/k: a native <button> item keeps its own Tab stop; landing twice on the same item no longer
  leaks its tabindex; after the focused item is removed (a hidden card) the next j goes on from
  its slot when that slot is on screen.
- An abandoned `g` no longer swallows a modifier chord (g, then Mod+K opened the browser search).
- A hover card above a dialog no longer switches its Tab trap off (player, Modal, wizard,
  Lightbox): new layerStack `anyBlockingLayerAbove`.
- "Manage views…" closes its menu before opening the dialog, through a shared `closeThenAct`
  that ActionMenu now uses too.
- Copy: the EN welcome says "Feed"; the EN unreachable reason no longer claims a change;
  stale comments about PlayerModal's scroll lock and dialog contract.

frontend/src/components/PlayerModal.tsx

@@ -27,7 +27,13 @@ import {
 import Avatar from "./ui/Avatar";
 import AddToPlaylist from "./AddToPlaylist";
 import { PopoverSurface, useAnchoredPopover } from "./ui/AnchoredPopover";
-import { pushLayer, removeLayer, anyLayerAbove, escapeHandled } from "../lib/layerStack";
+import {
+  pushLayer,
+  removeLayer,
+  anyBlockingLayerAbove,
+  anyLayerAbove,
+  escapeHandled,
+} from "../lib/layerStack";
 import { trapTab, useDialogChrome } from "./ui/dialogFocus";
 import DownloadButton from "./DownloadButton";
 import { api, type Video, type VideoStatus } from "../lib/api";
@@ -399,7 +405,7 @@ export default function PlayerModal({
 
   useKeyScope("ytPlayer");
 
-  // Keyboard shortcuts + background scroll lock. The chords live in the shared keymap (`ytPlayer`
+  // Keyboard shortcuts. The chords live in the shared keymap (`ytPlayer`
   // scope) so the help sheet lists them; only the behaviour behind each id is here.
   // These fire only while focus is on our page, not inside the cross-origin player iframe — so
   // we focus the modal card on open and again on player-ready (autoplay can grab focus).
@@ -424,10 +430,11 @@ export default function PlayerModal({
       nudgeSeek(secs);
     };
     const onKey = (e: KeyboardEvent) => {
-      // The shared dialog Tab trap — only while nothing is layered above the player: a Modal opened
-      // over it (the download dialog) traps for itself.
+      // The shared dialog Tab trap — only while nothing that owns the keyboard is layered above the
+      // player: a Modal opened over it (the download dialog) traps for itself. The title's hover card
+      // does not, so it must not switch the trap off.
       if (e.key === "Tab") {
-        if (layerIdRef.current != null && anyLayerAbove(layerIdRef.current)) return;
+        if (layerIdRef.current != null && anyBlockingLayerAbove(layerIdRef.current)) return;
         if (dialogRef.current) trapTab(e, dialogRef.current, cardRef.current);
         return;
       }