test(coverage): enable coverage reporting with lcov for Vitest

package.json

@@ -39,6 +39,7 @@
     "@types/node": "^20.0.0",
     "@typescript-eslint/parser": "^6.7.4",
     "@vercel/ncc": "^0.38.3",
+    "@vitest/coverage-v8": "^3.1.2",
     "eslint": "^8.51.0",
     "eslint-plugin-github": "^4.10.1",
     "eslint-plugin-jest": "^27.4.2",

vitest.config.ts

@@ -6,7 +6,7 @@ export default defineConfig({
     environment: 'node',
     include: ['__tests__/**/*.test.ts'],
     coverage: {
-      reporter: ['text', 'json', 'html'],
+      reporter: ['text', 'json', 'html', 'lcov'],
     },
   },
 });