Initial commit: Deklinationstrainer German declension trainer

Vite + React app for daily German declension practice with
localStorage-backed progress. Includes Coolify deploy instructions.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

vite.config.js

@@ -0,0 +1,6 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+
+export default defineConfig({
+  plugins: [react()],
+})