ci(release): run vitest between Lint and Build

Phase 4 added a vitest characterization suite. Hook it into the release
workflow so a failing test blocks the draft release alongside lint and
build. Ordering matches the per-phase quality gates: Lint, Test, Build.

.github/workflows/release.yml

@@ -40,6 +40,9 @@ jobs:
       - name: Lint (eslint)
         run: npm run lint
 
+      - name: Test (vitest)
+        run: npm test
+
       - name: Build
         run: npm run build