Keep CI test stage focused: drop build step

The Lint → Test → Security pattern keeps each stage to a single concern.
`npm run build` belonged to test only to publish a PR-preview artifact;
release.yml already handles production builds, and developers can run
`npm run build` locally. Removing it from the test stage:

- aligns with code-standards/ci/pipeline-structure.md
- shaves ~70s off PR CI time
- removes the "dist" artifact upload (coverage upload stays)

.github/workflows/ci.yml

@@ -62,14 +62,6 @@ jobs:
       - run: npm ci
       - name: Testes com cobertura
         run: npm run test:coverage
-      - run: npm run build
-      - uses: actions/upload-artifact@v4
-        with:
-          name: dist
-          path: |
-            main.js
-            manifest.json
-            styles.css
       - uses: actions/upload-artifact@v4
         if: always()
         with: