fix: add package.json to dashboard Dockerfile build stage

Ensures workspace resolution works correctly during Next.js build.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: VladUZH

apps/dashboard/Dockerfile

@@ -14,6 +14,7 @@ WORKDIR /app
 
 COPY --from=deps /app/node_modules ./node_modules
 
+COPY package.json package-lock.json ./
 COPY packages/shared/ ./packages/shared/
 COPY apps/dashboard/ ./apps/dashboard/
 COPY tsconfig.base.json ./