chore: remove Stripe — replaced by Orange Money / Wave payment gateway

feat: Claude Sonnet 4.6 provider + Stripe billing automation

feat(billing): complete billing system, push notifications, and tech debt fixes

refactor(debt): resolve all 10 technical debt items from audit

feat: backlog P0→P3 — toast system, payments, tenant isolation, feedback handler, i18n parity

fix(security): wire auth middleware chain in app.ts preHandler