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

fix: resolve 401/400 errors by centralizing API client and injecting organizationId in backend

feat: migrate to multi-tenant SaaS architecture with JWT auth and BullMQ notifications

Refactor: Technical Debt Repayment (Clean Dashboard, Strict Typing, Pino Logging, SQL Migration)