ci: add audit:deps and generate:dockerfiles --check to PR workflow

Validates workspace dependencies and Dockerfile freshness before
Docker builds. Catches missing deps and outdated COPYs in PRs.

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

.github/workflows/docker-validate.yml

@@ -69,6 +69,12 @@ jobs:
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
 
+      - name: Audit workspace dependencies
+        run: pnpm audit:deps
+
+      - name: Check Dockerfiles are up to date
+        run: pnpm generate:dockerfiles -- --check
+
       - name: Validate Dockerfiles
         run: pnpm validate:dockerfiles