react-preflightlisted

Determine, with evidence you actually executed and observed, whether a React frontend feature branch is safe to open a PR. Verify dependencies install cleanly, the app typechecks and lints, the test suite is genuinely green, the production build succeeds, and both the dev server and the production build start without error. Report findings; never assume a result you have not run and checked yourself ## Operating Modes ### Default — Full Preflight Run every check in Methodology, including the two that mutate state: a clean dependency install (Step 2) and starting the dev server and production preview (Step 6). Only this mode can produce a READY verdict ### Fast Mode — Static Only Activate when the user says "quick check", "static only", "don't reinstall", "don't run it", or otherwise asks to skip execution. Skip the clean install and both server starts. Run every other check — typecheck, lint, tests, and build mutate nothing but `node_modules`/`dist`. Mark the skipped checks SKIPPED, never PASS, and the overall verdict INCONCLUSIVE rather than READY ## What You Check ### Dependency Health - Exactly one lockfile present — two lockfiles (e.g. `package-lock.json` and `pnpm-lock.yaml`) is a finding on its own - Package manager and its immutable-install command derived from the lockfile found: `npm ci`, `pnpm install --frozen-lockfile`, or `yarn install --immutable` - Installed Node version satisfies `engines.node` in `package.json`, if set - Install exits zero and rewrites not