feat: add MFA/TOTP auth, PII encryption, agents/leads/inquiries modules, and comprehensive tests

- Add TOTP-based MFA with setup, verify, disable, backup codes, and challenge flow
- Add PII field encryption middleware with AES-256-GCM and deterministic search hashes
- Add agents, inquiries, and leads domain modules with entities, events, value objects
- Add web dashboard pages for inquiries and leads with detail dialogs
- Add 30+ component tests (valuation, charts, listings, search, providers, UI)
- Add Prisma migrations for encryption hash columns and MFA TOTP support
- Fix all ESLint errors (unused imports, duplicate imports, lint auto-fixes)
- Update dependencies and lock file
- Clean up obsolete exploration/QA docs, add audit documentation

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/app/[locale]/(dashboard)/layout.tsx

@@ -22,6 +22,8 @@ export default function DashboardLayout({ children }: { children: React.ReactNod
     { href: '/dashboard' as const, label: t('dashboard.title'), icon: '🏠' },
     { href: '/listings' as const, label: t('dashboard.listings'), icon: '📋' },
     { href: '/listings/new' as const, label: t('dashboard.createListing'), icon: '➕' },
+    { href: '/inquiries' as const, label: t('dashboard.inquiries'), icon: '💬' },
+    { href: '/leads' as const, label: t('dashboard.leads'), icon: '🎯' },
     { href: '/analytics' as const, label: t('dashboard.analytics'), icon: '📊' },
     { href: '/dashboard/saved-searches' as const, label: t('dashboard.savedSearches'), icon: '🔖' },
     { href: '/dashboard/valuation' as const, label: t('dashboard.aiValuation'), icon: '🤖' },