ci: check locale source freshness

Author: Wonderforge-Lab

.github/workflows/validate.yml

@@ -24,6 +24,19 @@ jobs:
       - run: python tests/test_generated_views.py
       - run: python tests/test_markdown_links.py
       - run: python tests/test_locale_invariants.py
+      - name: Check localized source freshness
+        env:
+          BEFORE: ${{ github.event.before }}
+          DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
+        run: |
+          if [ "${{ github.event_name }}" = "pull_request" ]; then
+            base="${{ github.event.pull_request.base.sha }}"
+          elif [ "$BEFORE" = "0000000000000000000000000000000000000000" ]; then
+            base="$(git merge-base "origin/$DEFAULT_BRANCH" "$GITHUB_SHA")"
+          else
+            base="$BEFORE"
+          fi
+          python tests/test_locale_freshness.py "$base" "$GITHUB_SHA"
       - run: python tests/test_bridge_config.py
       - run: python tests/test_tag_promotion.py
       - name: Enforce tag-promotion separation