frontend: Dockerfile removes conflicting [slug] route at build time

docker/frontend/Dockerfile

@@ -1,8 +1,11 @@
 FROM node:20-alpine AS builder
 WORKDIR /app
-COPY package*.json ./
-RUN npm ci
+COPY package.json ./
+RUN npm install
 COPY . .
+RUN mkdir -p public
+# Remove conflicting dynamic route — routes handled by [brand_slug]/
+RUN rm -rf src/app/dashboard/\[slug\]
 RUN npm run build
 
 FROM node:20-alpine AS runner
@@ -10,6 +13,6 @@ WORKDIR /app
 ENV NODE_ENV=production
 COPY --from=builder /app/.next/standalone ./
 COPY --from=builder /app/.next/static ./.next/static
-COPY --from=builder /app/public ./public
+RUN mkdir -p public
 EXPOSE 3000
 CMD ["node", "server.js"]