This is a React v18 and Node >= 24.13.0 app. Everything should be written in TypeScript.
Use vite. I may have specific opinions about other various JS
libraries so ask me if I have an opinion if it's not clear what library
to use.
Use vitest for tests. Test coverage must be > 90%. You may use
Playwright.
Write tests using the red-green-refactor methodology (write a test that fails for the correct reason, write an implementation that allows the test to pass, refactor the changes or other parts of the app to make the design clean while keeping the tests green).