fix: make Supabase optional and add assetPrefix support

- lib/supabase.ts: Return null when credentials missing instead of crash
- next.config.js: Add assetPrefix and basePath for VibeCoder proxy
- package.json: Use generic template name (v0.2.0)

next.config.js

@@ -1,12 +1,17 @@
 /** @type {import('next').NextConfig} */
 const nextConfig = {
   reactStrictMode: true,
-  // Note: 'output: standalone' is set during Docker build, not in dev mode
+  
+  // Support VibeCoder proxy paths (e.g., /projekte/[id]/preview/)
+  assetPrefix: process.env.ASSET_PREFIX || undefined,
+  basePath: process.env.BASE_PATH || undefined,
+  
   experimental: {
     serverActions: {
       bodySizeLimit: '2mb',
     },
   },
+  
   images: {
     remotePatterns: [
       {