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/ui/ActionMenu.tsx

@@ -1,6 +1,6 @@
 import { Fragment, useState, type ReactNode } from "react";
 import { ChevronRight, MoreHorizontal } from "lucide-react";
-import { PopoverItem, PopoverSurface, useAnchoredPopover } from "./AnchoredPopover";
+import { PopoverItem, PopoverSurface, closeThenAct, useAnchoredPopover } from "./AnchoredPopover";
 
 // A reusable "⋯ more actions" overflow menu: a compact trigger that opens a list of one-shot actions.
 // Built on the R8 AnchoredPopover platform (arrows/typeahead/Escape/anchor-flip), same as ViewSwitcher
@@ -82,17 +82,8 @@ export function MenuItemList({
               disabled={it.disabled}
               label={it.label}
               title={it.title}
-              onSelect={() => {
-                // Close FIRST, act once the menu has handed the focus back. floating-ui returns the
-                // focus to the trigger from a microtask queued as the menu unmounts, so an action run
-                // in the same batch had its focus taken back by it: measured in Chrome (E11 S2), a
-                // confirm dialog opened from the rail's menu landed its focus on Cancel and lost it
-                // 7 ms later to the row BEHIND its scrim, where Enter activated the row. A fresh task
-                // runs after that microtask — and a dialog opened there captures the trigger, not a
-                // dying menu item, as the element to restore the focus to.
-                onClose();
-                setTimeout(it.onSelect, 0);
-              }}
+              // Any row may open a dialog (a confirm), so every row closes first — see closeThenAct.
+              onSelect={() => closeThenAct(onClose, it.onSelect)}
               className={`${ROW}${it.danger ? " text-danger" : ""}`}
             >
               {it.icon && (