feat: statusbalk met versie en builddatum

Voegt sticky statusbalk toe aan de onderkant van de app met:
- Copyright melding
- App-versie uit package.json (NEXT_PUBLIC_APP_VERSION)
- Builddatum ingesteld op het moment van de build (NEXT_PUBLIC_BUILD_DATE)

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

next.config.ts

@@ -1,7 +1,11 @@
-import type { NextConfig } from "next";
+import type { NextConfig } from "next"
+import pkg from "./package.json"
 
 const nextConfig: NextConfig = {
-  /* config options here */
-};
+  env: {
+    NEXT_PUBLIC_APP_VERSION: pkg.version,
+    NEXT_PUBLIC_BUILD_DATE: new Date().toISOString(),
+  },
+}
 
-export default nextConfig;
+export default nextConfig