MVP: E2E happy path + live HITL

[kuyacarlo]

Parent: #74

Scope

Documented path from cold start → ingest → push → pending HITL → approve/reject on live API (mocks only as fallback).

Files

• docker-compose.yml
• frontend/services/api.ts, HITL components
• docs/ONBOARDING.md / docs/mvp/

DoD

• Runbook in docs
• HITL card works with backend up
• Smoke script or checklist committed