feat(embed): GitHub/GitLab-friendly diagram embed (SVG + iframe page)

.github/workflows/pr-health-checks.yaml

@@ -68,10 +68,24 @@ jobs:
       - name: Check build
         run: npm run build
 
-      - name: Run unit tests
+      - name: Verify test-only seams are tree-shaken from production bundles
+        # `__test_internals__` is exported from svgToPng.ts so the Vitest suite
+        # can swap the worker; tree-shaking should drop it from the prod bundle.
+        # This guard fails the PR if a future refactor inadvertently lets it leak.
+        run: |
+          if grep -r --include='*.js' '__test_internals__' standalone/webapp/dist; then
+            echo "ERROR: __test_internals__ leaked into production bundle." >&2
+            exit 1
+          fi
+
+      - name: Run unit tests (library)
         run: npm run test
         working-directory: library/
 
+      - name: Run unit tests (webapp)
+        run: npm run test
+        working-directory: standalone/webapp/
+
   e2e-tests:
     needs: [detect-changes]
     if: needs.detect-changes.outputs.should-skip != 'true' && needs.detect-changes.outputs.code == 'true'