An Electron client for the desktop store

The desktop store put the catalog on ordinary computers, and then asked people to
open a terminal — which on Windows is not even a workable ask, because the
installer is `curl … | sh`. This is the window: a grid of cards, one click to
install a title into the application menu, one to play it, one to remove it.

The CLI stays the product. Every action runs `desktop_store.py --json`, so there
is one catalog logic, one state file and one delete guard; the window never
touches the filesystem itself. That is also why the engine grew `--json` first
rather than this app growing a parser for prose.

It doubles as the Windows install path: with no store on the machine, the app
downloads the engine, the shared core and a config into the same folder the shell
installer would use — Node's https, no curl. An engine older than 1.1.0 cannot be
driven from a window, so the client checks the version and offers to refresh it
instead of failing on the first call.

Deliberate choices worth knowing:

- No renderer framework and no build step. Plain HTML, CSS and JS, one runtime
  dependency. The whole UI is readable in one sitting.
- `contextIsolation` on, `nodeIntegration` off, `sandbox` on, a CSP that permits
  only the app's own script and stylesheet plus images over HTTPS. The renderer
  can do exactly what preload.js exposes and nothing else.
- English and Hungarian, following the system language. The CLIs and the docs stay
  English; this is the one end-user surface where that is not enough.
- `ENGINES` is a list with one entry. The RetroArch store has the same command
  shape, so adding it is an entry, not a rewrite.

Two ways to test it without a working installation in the way: `npm run smoke`
drives the bridge with no window at all, and `npm run uitest` loads the window
once and reports what rendered — the only way a renderer error would otherwise be
noticed, since the main process log stays empty. Both accept a sandbox store
through STORE_ROOT / SMOKE_HOME.

Verified on macOS arm64, including the packaged .app: the store is found, ten
titles list, a sync installs three, and the window renders them as installed with
their Play and Remove buttons. Linux and Windows are unproven, as they are for the
CLI itself.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

lib/i18n.js

@@ -0,0 +1,94 @@
+'use strict'
+// Two languages, the way the public site has them. The CLI and the docs stay
+// English; this is the one end-user surface where Hungarian matters.
+//
+// Catalog text — titles, descriptions — is never translated here: it arrives
+// from the store as it was published.
+
+const STRINGS = {
+  en: {
+    appName: 'WarpEngine Store',
+    syncAll: 'Install all',
+    refresh: 'Refresh',
+    install: 'Install',
+    update: 'Update',
+    play: 'Play',
+    open: 'Open',
+    remove: 'Remove',
+    installed: 'installed',
+    native: 'native',
+    hosted: 'hosted',
+    hostedHint: 'Opens in your browser — needs the network',
+    nativeHint: 'Installed on this machine — works offline',
+    updateAvailable: 'update available',
+    log: 'Log',
+    noGames: 'No installable titles in the catalog.',
+    setupTitle: 'Set up the store',
+    setupBody: 'The store engine is not on this machine yet. It can be downloaded now — the same files the shell installer would place, in the same folder.',
+    setupAction: 'Download the store',
+    setupWorking: 'Setting up…',
+    oldEngineTitle: 'The store needs refreshing',
+    oldEngineBody: 'The store engine on this machine is older than this client can drive. Refreshing it downloads the current engine and keeps your settings and installed games.',
+    oldEngineAction: 'Refresh the store',
+    noPythonTitle: 'Python 3 is required',
+    noPythonBody: 'The store is a Python program, so Python 3 has to be installed. Install it, then reopen this window.',
+    pythonLink: 'python.org/downloads',
+    paths: 'Where things go',
+    openStoreFolder: 'Open the store folder',
+    openMenuFolder: 'Open the menu folder',
+    busy: 'Working…',
+    failed: 'failed',
+    removed: 'removed',
+    upToDate: 'Everything is up to date.',
+    of: 'of'
+  },
+  hu: {
+    appName: 'WarpEngine Store',
+    syncAll: 'Mind telepítése',
+    refresh: 'Frissítés',
+    install: 'Telepítés',
+    update: 'Frissítés',
+    play: 'Indítás',
+    open: 'Megnyitás',
+    remove: 'Eltávolítás',
+    installed: 'telepítve',
+    native: 'natív',
+    hosted: 'hosztolt',
+    hostedHint: 'A böngészőben nyílik meg — internet kell hozzá',
+    nativeHint: 'Erre a gépre telepítve — internet nélkül is megy',
+    updateAvailable: 'frissítés elérhető',
+    log: 'Napló',
+    noGames: 'Nincs telepíthető cím a katalógusban.',
+    setupTitle: 'A store beállítása',
+    setupBody: 'A store motorja még nincs ezen a gépen. Most letölthető — ugyanazok a fájlok, ugyanabba a könyvtárba, ahová a shell-telepítő tenné.',
+    setupAction: 'Store letöltése',
+    setupWorking: 'Beállítás…',
+    oldEngineTitle: 'A store frissítésre vár',
+    oldEngineBody: 'A gépen lévő store-motor régebbi, mint amit ez a kliens vezérelni tud. A frissítés letölti a mostani motort, a beállításaid és a telepített játékok pedig megmaradnak.',
+    oldEngineAction: 'Store frissítése',
+    noPythonTitle: 'Python 3 kell hozzá',
+    noPythonBody: 'A store egy Python program, tehát Python 3 kell a gépre. Telepítsd, majd nyisd meg újra ezt az ablakot.',
+    pythonLink: 'python.org/downloads',
+    paths: 'Hova kerül',
+    openStoreFolder: 'Store könyvtár megnyitása',
+    openMenuFolder: 'Menü könyvtár megnyitása',
+    busy: 'Dolgozom…',
+    failed: 'hiba',
+    removed: 'eltávolítva',
+    upToDate: 'Minden naprakész.',
+    of: '/'
+  }
+}
+
+const FALLBACK = 'en'
+
+function pick (locale) {
+  const short = String(locale || '').slice(0, 2).toLowerCase()
+  return STRINGS[short] ? short : FALLBACK
+}
+
+function dict (locale) {
+  return STRINGS[pick(locale)]
+}
+
+module.exports = { FALLBACK, STRINGS, dict, pick, languages: Object.keys(STRINGS) }