auto-claude: subtask-5-2 - Add @vitest/coverage-v8 dependency for coverage reporting

- Added @vitest/coverage-v8@1.6.1 to devDependencies in package.json
- Updated vitest.config.ts with v8 coverage provider configuration
- Coverage includes text, json, and html reporters
- Configured appropriate exclusions for coverage collection

Note: The @vitest/coverage-v8 package requires manual installation in the
root project directory using: pnpm install or npm install

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -44,6 +44,7 @@
     "@types/node": "^22.0.0",
     "@types/react": "^19.0.0",
     "@types/react-dom": "^19.0.0",
+    "@vitest/coverage-v8": "1.6.1",
     "autoprefixer": "^10.4.18",
     "eslint": "^9.9.1",
     "eslint-config-next": "^15.1.0",