Migrate App to Flows Infrastructure

Orchestrates the full migration of a legacy Dune app to the new Flows app hosting (appsApi). Works through each area in order, skipping any already in the correct state.

Step 1 — Audit current state

Read app.json, package.json, vite.config.ts, and manifest.json (if present).

Report a concise summary before making any changes:

Migration audit:
✗ app.json: missing infra field → will add "infra": "appsApi"
✗ Auth: DuneAuthProvider in use → will run setup-flows-auth
✗ manifest.json: missing → will create
✓ Deploy script: already uses @cognite/cli

Then proceed through Steps 2–5.