feat(keys): the conversation list walks with j/k; the cheat sheet names keys in the reader's language

E11 S5 — the HU/EN sweep and the keyboard-only pass over every module.

- The keyboard cheat sheet printed "Space" and "Menu" on a Hungarian sheet: a keycap that carries a
  WORD (not a legend every layout prints alike, like Esc, Ctrl or Enter) is now named by the caller in
  the reader's language (`formatChord(chord, words)`, `keys.cap.*`: Szóköz / Menü).
- The Plex player's ⌫/Esc line said "Stop & back to feed", but the player goes back to wherever it
  was opened from (Home, a Plex page): "Stop & go back" / "Leállítás és vissza".
- Messages: the conversation list is a keyboard list (NavGrid + navItemAttrs, the name button is the
  open element; the pop-out button keeps its own Enter). D1 covers every list whose rows open one
  thing; this one was missed in S4. Notification cards have no single open action and stay out, like
  the download queue.

Sweep, measured: every static `t("…")` key used in the source exists in both languages (the only
misses are template prefixes); the HU values equal to EN are proper nouns and loanwords (Admin, Plex,
Trakt, Shorts). Palette in Hungarian: "téma" makes "Téma: Midnight" the active row ahead of the channel
"Topik - mindig témában", live region "7 találat".

Keyboard-only pass in Chrome, Hungarian UI — 1024×768: every `g` chord lands on its module, `j` rings
the first item (solid 2px accent) on Home, Feed, Channels, Playlists, Plex and Downloads, `s` focuses
the search on Feed, Channels, Playlists and Plex, no page scrolls sideways. 3440×1440: `j` → → ↓
walks Home, Feed (8 columns: 0 → 1 → 9), Channels, Playlists, Plex and Downloads, no sideways scroll.
The help sheet lists every line translated; inside the Plex player "Szóköz / K" and "⌫ / Esc
Leállítás és vissza". Messages: a real `j` rings the row, Enter opens the thread.

frontend/src/lib/keymap.sequence.test.ts

@@ -149,8 +149,9 @@ describe("the page-level rows", () => {
   });
 
   it("render as the keys to press, step by step", () => {
-    expect(formatChord("g h")).toBe("G H");
-    expect(formatChord("g ,")).toBe("G ,");
+    const words = { Space: "Space", ContextMenu: "Menu" };
+    expect(formatChord("g h", words)).toBe("G H");
+    expect(formatChord("g ,", words)).toBe("G ,");
   });
 
   // `g h` shares Home's line with Shift+W; leaving out an unreachable chord must not take that with it.

frontend/src/lib/keymap.test.ts

@@ -213,11 +213,19 @@ describe("helpLines", () => {
 });
 
 describe("formatChord", () => {
+  const words = { Space: "Szóköz", ContextMenu: "Menü" };
+
   it("renders glyphs and upper-cases the letter", () => {
-    expect(formatChord("ArrowLeft")).toBe("←");
-    expect(formatChord("Backspace")).toBe("⌫");
-    expect(formatChord("Shift+ArrowRight")).toBe("⇧ →");
-    expect(formatChord("k")).toBe("K");
-    expect(formatChord("Space")).toBe("Space");
+    expect(formatChord("ArrowLeft", words)).toBe("←");
+    expect(formatChord("Backspace", words)).toBe("⌫");
+    expect(formatChord("Shift+ArrowRight", words)).toBe("⇧ →");
+    expect(formatChord("k", words)).toBe("K");
+  });
+
+  // A key whose cap carries a word is named in the reader's language: the Hungarian sheet said "Space".
+  it("names a word key in the caller's language", () => {
+    expect(formatChord("Space", words)).toBe("Szóköz");
+    expect(formatChord("ContextMenu", words)).toBe("Menü");
+    expect(formatChord("Shift+F10", words)).toBe("⇧ F10");
   });
 });

frontend/src/lib/keymap.ts

@@ -195,7 +195,7 @@ export const SHORTCUTS = [
   { id: "stats", scope: "plexPlayer", keys: ["d"], labelKey: "keys.stats" },
   // Two rows, one help line: ⌫ is the plain "stop & out", Escape is the layer-aware cascade (defer to
   // anything above → cancel auto-skip → close the topmost player overlay → close). Sharing a labelKey
-  // keeps them a single "⌫ Esc  Stop & back to feed" row in the sheet.
+  // keeps them a single "⌫ Esc  Stop & go back" row in the sheet.
   { id: "back", scope: "plexPlayer", keys: ["Backspace"], labelKey: "keys.back" },
   {
     id: "escape",
@@ -558,28 +558,33 @@ const GLYPHS: Record<string, string> = {
   ArrowUp: "↑",
   ArrowDown: "↓",
   Backspace: "⌫",
-  ContextMenu: "Menu", // the dedicated menu key; "ContextMenu" is a DOM name, not a keycap
   Escape: "Esc",
   Shift: "⇧",
 };
 
+/** The keys a keycap names with a WORD rather than a legend every layout prints alike (Esc, Ctrl,
+ *  Enter): the caller supplies them in the reader's language — a Hungarian sheet said "Space". */
+export type KeycapWords = Readonly<Record<"Space" | "ContextMenu", string>>;
+
 const isMac = (): boolean =>
   typeof navigator !== "undefined" && /mac|iphone|ipad/i.test(navigator.userAgent);
 
 /** A chord as the help sheet shows it: `Mod+Shift+z` → `Ctrl ⇧ Z` (`⌘ ⇧ Z` on a Mac), and a
  *  sequence step by step: `g h` → `G H`. */
-export function formatChord(chord: string): string {
-  return stepsOf(chord).map(formatStep).join(" ");
-}
-
-function formatStep(chord: string): string {
-  return chord
-    .split("+")
-    .map((part, i, all) => {
-      if (part.toLowerCase() === "mod") return isMac() ? "⌘" : "Ctrl";
-      if (i < all.length - 1) return GLYPHS[part] ?? part;
-      return GLYPHS[part] ?? (part.length === 1 ? part.toUpperCase() : part);
-    })
+export function formatChord(chord: string, words: KeycapWords): string {
+  const name = (part: string): string | undefined =>
+    GLYPHS[part] ?? words[part as keyof KeycapWords];
+  return stepsOf(chord)
+    .map((step) =>
+      step
+        .split("+")
+        .map((part, i, all) => {
+          if (part.toLowerCase() === "mod") return isMac() ? "⌘" : "Ctrl";
+          if (i < all.length - 1) return name(part) ?? part;
+          return name(part) ?? (part.length === 1 ? part.toUpperCase() : part);
+        })
+        .join(" "),
+    )
     .join(" ");
 }