KnowledgeVault AI module-spec M-01

M-01 delivers end-to-end expert registration for the KnowledgeVault platform: a mobile signup form collecting name, email, phone, trade, specialties and experience; the POST /api/experts/signup endpoint that atomically creates the experts row, a Supabase Auth user with role=expert in app_metadata, and a Stripe Connect Express account for payouts; and a reusable JWT auth middleware consumed by M-02 and M-04. This module is the cold-start unlock — no sessions, captures or payments can occur until