chore: docker config, package.json and setup script updates

docker/Dockerfile

@@ -12,6 +12,9 @@ RUN npm ci
 # Copy source code
 COPY . .
 
+# Ensure public exists (Next.js may not have one; COPY in runner stage requires it)
+RUN mkdir -p public
+
 # Generate Prisma client
 RUN npx prisma generate