Build the first version of a web app from this idea: {{app_idea}} It is for {{target_users}}. Features it must have in version 1: {{must_have_features}}. Look and feel: {{visual_style}}. Before writing code, show me a short plan: 1. A one-paragraph summary of the app and the problem it solves 2. The pages, and what each one shows and lets people do 3. The main user flows, step by step 4. The data to store, as tables with fields and how they relate 5. Sign-in and permissions: who can see, create, edit, and delete what Keep version 1 small and list anything that can wait under "Later". Make every page responsive, with empty, loading, and error states. If something important is unclear, ask me up to five questions instead of guessing, then build once I confirm the plan.