Final gate of the Flows app certification flow for external submission. Verifies that flows-app-brief, flows-code-review, and flows-design-review have all been run and are in a passing state (App-Brief.md complete, 0 Must Fix in latest code review, design average ≥ 3.8), then runs `npx @cognite/cli apps submit` to zip the repo and pre-populate the submission form. Use when the user asks to submit a Flows app for certification, run flows-external-app-submit, or finalize an app for external review.