feat(e24): reach the Home surface — the landing toggle, a palette command, Shift+W

S4's reachability half. Home already led the nav order; what was missing was every
way IN other than the rail.

- Settings → Appearance → Startup: "Start on Home", the documented escape hatch for
  the landing override. Deliberately still localStorage and not a server pref —
  `loadInitialPage` answers before /api/me lands, and a landing module decided after
  the first paint is a visible jump. Its two stored values are now ONE exported
  constant, so the writer and the boot-time reader cannot drift on a magic string.
- The command palette gets "Meglepetés" / "Surprise me": it navigates to Home and
  rerolls the hero on arrival. No second "Mit nézzek?" row beside it — the Home
  module row already matches that phrase through its descriptive title.
- A global Shift+W jumps to Home. A chord, not a bare `w`: the Plex player binds bare
  letters and `w` sits on `s`, so a blind reach for the subtitle key would have thrown
  a viewer out of the film.

The palette's request crosses a lazy module boundary, so it is a token that waits
(lib/homeIntent) rather than an event fired into an empty room. Browser-measured:
taken with a compare-and-clear, because StrictMode's double-invoked mount effect
otherwise rerolled twice and landed on the page two picks deep.

HU/EN parity kept; UAT on localdev in both languages, including the empty shelf.

frontend/src/components/navigation.dom.test.ts

@@ -15,7 +15,7 @@ vi.mock("../lib/storage", async (importOriginal) => {
   return { ...actual, getAccountRaw: (k: string) => stored[k] ?? null };
 });
 
-import { loadInitialPage, channelViewFrom } from "./navigationInit";
+import { loadInitialPage, channelViewFrom, START_ON_HOME } from "./navigationInit";
 import { LS } from "../lib/storage";
 
 const setUrl = (search: string) => window.history.replaceState(null, "", search || "/");
@@ -66,12 +66,12 @@ describe("loadInitialPage precedence", () => {
     expect(loadInitialPage()).toBe("home");
   });
   it("opting out restores the account's stored landing page", () => {
-    stored[LS.startOnHome] = "0";
+    stored[LS.startOnHome] = START_ON_HOME.off;
     stored[LS.page] = "downloads";
     expect(loadInitialPage()).toBe("downloads");
   });
   it("opted out with no / invalid stored page still defaults to feed", () => {
-    stored[LS.startOnHome] = "0";
+    stored[LS.startOnHome] = START_ON_HOME.off;
     expect(loadInitialPage()).toBe("feed");
     stored[LS.page] = "nope";
     expect(loadInitialPage()).toBe("feed");