fix: serve uploaded images via API route (public/ is read-only in production)

Next.js bakes public/ at build time — dynamically uploaded files were
never served in Docker standalone mode. Store uploads in data/uploads/
and serve via /api/uploads/ with a rewrite for backward compatibility.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

memento-note/next.config.ts

@@ -4,6 +4,16 @@ const nextConfig: NextConfig = {
   // Enable standalone output for Docker
   output: 'standalone',
 
+  // Serve dynamically uploaded files via API route (public/ is read-only in production)
+  async rewrites() {
+    return [
+      {
+        source: '/uploads/:path*',
+        destination: '/api/uploads/:path*',
+      },
+    ]
+  },
+
   // Image optimization (enabled for better performance)
   images: {
     formats: ['image/avif', 'image/webp'],