Check translation contracts offline, add Swedish to the installer and enable the website languages

- Offline checks for terminal and website catalogs reject translations that change commands, paths, identifiers or placeholders
- Terminal and documentation texts that broke those contracts are corrected in every language
- Swedish can be chosen in the stable and beta installers
- The website routes, language switcher and exported pages cover the eight languages, with the shared website texts in each of them
- Website documentation translations are generated only when requested
- From PR #475 by @jcastro

web/app/layout.tsx

@@ -8,13 +8,14 @@ const inter = Inter({ subsets: ["latin"] })
  * Minimal root layout — the localized layout under [locale]/ does the
  * real work (provider, navbar, etc.) but cannot own <html>/<body> tags
  * because Next.js requires those at the root level. Lang is set to the
- * default locale here and refined client-side from inside the locale
- * layout so the page still renders correctly with JS disabled (defaults
- * to English) and switches to the active locale once hydrated.
+ * default locale here; scripts/localize-export.mjs sets the exported
+ * document's language before search indexing, and LocaleHtmlSync keeps
+ * it in sync during client navigation. The root-only hydration suppression
+ * allows that intentional lang attribute change in the static export.
  */
 export default function RootLayout({ children }: { children: React.ReactNode }) {
   return (
-    <html lang="en" className="dark">
+    <html lang="en" className="dark" suppressHydrationWarning>
       <body className={`${inter.className} bg-background text-foreground antialiased`}>
         {children}
       </body>