fix: eliminate 2s LCP rendering delay from Directus timeout on Hero

The Hero server component awaited getMessages(locale) which called Directus
with a 2-second timeout. On testing.dk0.dev (or when Directus is unreachable),
this blocked the entire Hero render for ~2s → LCP 3.0s / 2320ms rendering delay.

Changes:
- Hero.tsx: remove getMessages() call entirely; use t() for all strings
- messages/en.json + de.json: add hero.badge, hero.line1, hero.line2 keys
- lib/i18n-loader.ts: invert lookup order — JSON first, Directus only as
  override for keys absent from JSON. Previously Directus was tried first
  for every key, causing ~49 parallel network requests per page load in
  HomePageServer (aboutT + projectsT + contactT + footerT translations).
  Now all JSON-backed keys return instantly without any network I/O.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/__tests__/components/Hero.test.tsx

@@ -5,6 +5,9 @@ import Hero from '@/app/components/Hero';
 jest.mock('next-intl/server', () => ({
   getTranslations: () => Promise.resolve((key: string) => {
     const messages: Record<string, string> = {
+      badge: 'Student & Self-Hoster',
+      line1: 'Building',
+      line2: 'Stuff.',
       description: 'Dennis is a student and passionate self-hoster.',
       ctaWork: 'View My Work',
       ctaContact: 'Get in touch',
@@ -13,11 +16,6 @@ jest.mock('next-intl/server', () => ({
   }),
 }));
 
-// Mock directus getMessages
-jest.mock('@/lib/directus', () => ({
-  getMessages: () => Promise.resolve({}),
-}));
-
 // Mock next/image
 interface ImageProps {
   src: string;