I want to build a small internal app as a non-coder using Claude Design and Codex. Give me 5 realistic app ideas that are simple enough to build as a local MVP. For each idea, include: - who the app is for - the pain point - the main workflow - the core features - what can be tested in the browser The app should be useful, but not too complex. Avoid ideas that need login, payment, real database setup, or third-party integrations in the first version.