tsconfig.typecheck.json

{
  "// note": "Standalone JSDoc typecheck config. Deliberately NOT named tsconfig.json so Next.js does not switch the project into TypeScript mode. Only files with a `// @ts-check` pragma are type-checked (checkJs is false). Run via `npm run typecheck`.",
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "moduleResolution": "bundler",
    "allowJs": true,
    "checkJs": false,
    "noEmit": true,
    "strict": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "resolveJsonModule": true,
    "types": ["node"]
  },
  "include": ["lib/**/*.js"],
  "exclude": ["**/*.test.js", "node_modules", ".next"]
}