fix(docker): copy pnpm-workspace.yaml before pnpm install

pnpm 11 reads onlyBuiltDependencies from pnpm-workspace.yaml, but it
wasn't being copied into the builder layer before install ran.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -15,7 +15,7 @@ ENV NEXT_PUBLIC_SITE_URL=$NEXT_PUBLIC_SITE_URL
 ENV NODE_ENV=production
 
 # Copy package files
-COPY package.json pnpm-lock.yaml* ./
+COPY package.json pnpm-lock.yaml* pnpm-workspace.yaml ./
 
 # Install pnpm and dependencies
 RUN corepack enable pnpm && pnpm install --frozen-lockfile