Fix: localize the PWA install prompt

The PWA install prompt was hardcoded English regardless of the selected UI
language (and the large English block tripped Chrome's translate popup on
Android). Add a pwa_install namespace to all 17 locales, switch the component
to useTranslations, and move <PWAInstallPrompt /> from (main)/layout into
(main)/[locale]/layout so it renders inside the IntlProvider. The title keeps
the dynamic {appName}, so per-domain branding still applies.

app/(main)/[locale]/layout.tsx

@@ -9,6 +9,7 @@ import { ProtocolLaunchHandlerProvider } from "@/components/protocol/protocol-la
 import { ProInterfaceRedirect } from "@/components/pro/pro-interface-redirect";
 import { PluginDialogHost } from "@/components/plugins/plugin-dialog-host";
 import { PluginConsentDialog } from "@/components/plugins/plugin-consent-dialog";
+import { PWAInstallPrompt } from "@/components/pwa-install-prompt";
 import { locales } from "@/i18n/routing";
 
 export default async function LocaleLayout({
@@ -41,6 +42,7 @@ export default async function LocaleLayout({
                   {children}
                   <PluginDialogHost />
                   <PluginConsentDialog />
+                  <PWAInstallPrompt />
                 </ProtocolLaunchHandlerProvider>
               </TourProvider>
             </EmbeddedBridgeProvider>