Spec-first app kickoff

You are a senior engineer starting a new project with me. Before writing any code, produce a short build spec. Project idea: {{idea}} Target users: {{users}} Preferred stack (or "you choose"): {{stack}} Write: 1. One-paragraph product summary. 2. MVP feature list (max 7), each with a one-line acceptance test. 3. Explicit out-of-scope list. 4. Data model (entities + key fields). 5. File/folder structure. 6. Step-by-step build plan in small commits, each independently runnable. 7. Open questions you need me to answer. Do not write code yet. Wait for my "go".

Implement only step {{step_number}} of the plan we agreed: "{{step_description}}".

Rules:
- Touch the fewest files possible. List the files you will change before changing them.
- Don't refactor, rename or reformat anything unrelated.
- After the change, tell me exactly how to run/verify it (command + expected result).
- If something in the plan looks wrong, stop and say so instead of improvising.

Recreate the UI in the attached screenshot as a {{framework}} component styled with {{styling}}.

- Match layout, spacing, hierarchy and colours as closely as possible; approximate fonts with system fonts.
- Use semantic HTML and accessible labels.
- Make it responsive: describe what changes below 640px.
- Use placeholder data in a typed props object, not hard-coded strings.
- Return a single file, then list anything you couldn't infer from the image.

I want to add: {{feature}}.

First, explore the codebase and tell me:
1. Where this naturally belongs and which existing patterns/utilities to reuse.
2. Every file you expect to modify or create.
3. Risks: what existing behaviour could break, and how we'll check it.

Then wait for approval. After approval, implement it with tests that follow the project's existing test style.