fix(audit): resolve remaining minor technical debt issues

feat: gold standards tests (15 days + STT + vision) & botName editable in AI setup

feat(admin): UX non-tech complète + i18n 4 langues

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

fix(admin): sidebar active states, responsive mobile drawer, correct nav labels

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

chore: update locale files

feat: wire i18n to dashboard, settings, users — complete locale files

feat: implement whatsapp templates management with security hardening, audit logs, and crm integration