i18n: paraglide setup mirroring played/plaza, de unprefixed + /en/ prefixed

- project.inlang/settings.json with locales [de, en], baseLocale de.
- messages/{de,en}.json hold the strings (tagline, blog labels, etc.).
- vite.config.ts: paraglideVitePlugin compiles to src/paraglide/
  (gitignored) on dev/build. Strategy: url → cookie →
  preferredLanguage → baseLocale. URL pattern keeps German at /:path
  (unprefixed) and English at /en/:path so existing URLs stay valid.
- server.tsx wraps the handler in paraglideMiddleware so AsyncLocalStorage
  carries the per-request locale into SSR.
- router.tsx adds rewrite { input: deLocalizeUrl, output: localizeUrl }
  so route matching stays locale-agnostic — the router sees /blog while
  URLs show /en/blog.
- cms.ts narrows getLocale()'s union back to the de|en pair the CMS
  supports, used as the default for find/findGlobal calls.
- Components/routes switch to m.foo() for user-visible strings; date
  formatting picks de-DE / en-GB from getLocale().
- Root html lang reads getLocale() so the document language flips per
  request.

Known minor: TanStack Start's { title } meta entry still serves the base
locale value (og:title and the description meta are localized correctly).
Will track separately.

src/server.tsx

@@ -1,7 +1,11 @@
 import handler from "@tanstack/react-start/server-entry";
+import { paraglideMiddleware } from "./paraglide/server.js";
 
 export default {
 	async fetch(req: Request): Promise<Response> {
-		return handler.fetch(req);
+		// paraglide reads the URL prefix / cookie / Accept-Language and binds the
+		// detected locale into AsyncLocalStorage for the duration of the request,
+		// so any `getLocale()` calls during SSR see the right value.
+		return paraglideMiddleware(req, () => handler.fetch(req));
 	},
 };