fix: Web standalone — set outputFileTracingRoot to repo root

In monorepo, Next.js standalone creates symlinks instead of real files.
Setting outputFileTracingRoot to repo root produces self-contained output.
Dockerfile updated to copy from correct standalone structure.

Co-Authored-By: Claude Opus 4 (1M context) <noreply@anthropic.com>

apps/web/next.config.js

@@ -7,6 +7,8 @@ const withNextIntl = createNextIntlPlugin('./i18n/request.ts');
 const nextConfig = {
   reactStrictMode: true,
   output: 'standalone',
+  // In monorepo, trace from repo root so standalone output includes all deps
+  outputFileTracingRoot: require('path').join(__dirname, '../../'),
   images: {
     remotePatterns: [
       {