# Phase 7 Research: Web App Shell and Diagnostic Start

## Findings

The existing Go backend can serve static assets without adding frontend build
tooling. For the first MVP UI, plain HTML/CSS/JavaScript is enough and keeps
the repo dependency-light.

The diagnostic APIs already provide all Phase 7 data:

- `POST /api/v1/diagnostic-sessions`
- `POST /api/v1/diagnostic-sessions/{id}/answers`
- `GET /api/v1/diagnostic-sessions/{id}`

## Recommended Shape

- Add `internal/webapp` with embedded static assets.
- Register web app routes from `httpapi.Handler`.
- Keep frontend files small and focused.
- Use fetch calls directly against existing API routes.

## Risks

- A mock UI would not prove the backend loop. The UI must call real APIs.
- A marketing-style landing page would distract from the core product surface.
- Overbuilding a frontend stack before interaction validation would violate
  YAGNI.