refactor: rename marketplace to storefront across the entire monorepo

Comprehensive rename of all marketplace references to storefront:
- API module: apps/api/src/modules/marketplace/ → storefront/
- Components: MarketplaceHeader → StorefrontHeader, MarketplaceShell →
  StorefrontShell, MarketplaceFooter → StorefrontFooter
- Types: marketplace-homepage.ts → storefront-homepage.ts
- Test files: employee-marketplace-* → employee-storefront-*
- All source code identifiers, imports, route paths, and strings
- Documentation (docs/), CI config (.gitlab-ci.yml), scripts
- Dashboard, admin, storefront workspace references
- Prisma field names preserved (isListedOnMarketplace, marketplaceRating,
  marketplaceFunnelEvent) as they map to database schema

Validation:
- API type-check: 0 errors
- Storefront type-check: 0 errors
- Dashboard type-check: 0 errors
- Full monorepo type-check: only pre-existing admin TS18046

apps/admin/src/app/dashboard/page.tsx

@@ -24,7 +24,7 @@ export default function AdminDashboardPage() {
       brand: 'RentalDriveGo',
       eyebrow: 'Operations command',
       platformOverview: 'RentalDriveGo admin dashboard',
-      subtitle: 'Monitor marketplace health, subscription coverage, renter activity, and operator actions from one control surface.',
+      subtitle: 'Monitor storefront health, subscription coverage, renter activity, and operator actions from one control surface.',
       liveSignal: 'Live platform signal',
       readiness: 'Operational readiness',
       readinessBody: 'Core admin workflows are connected and ready for platform support.',
@@ -36,14 +36,14 @@ export default function AdminDashboardPage() {
         ['Renters', 'Support renter trust workflows, blocking, and account recovery.', 'View all'],
         ['Audit logs', 'Trace every sensitive admin action across RentalDriveGo.', 'View logs'],
       ],
-      health: ['Tenant accounts', 'Marketplace identity', 'Admin audit trail'],
+      health: ['Tenant accounts', 'Storefront identity', 'Admin audit trail'],
     },
     fr: {
       kpis: ['Entreprises totales', 'Entreprises actives', 'Locataires totaux', 'Réservations totales'],
       brand: 'RentalDriveGo',
       eyebrow: 'Centre des opérations',
       platformOverview: 'Tableau de bord admin RentalDriveGo',
-      subtitle: 'Suivez la santé de la marketplace, les abonnements, l’activité des locataires et les actions opérateur depuis une même interface.',
+      subtitle: 'Suivez la santé de la storefront, les abonnements, l’activité des locataires et les actions opérateur depuis une même interface.',
       liveSignal: 'Signal plateforme en direct',
       readiness: 'Disponibilité opérationnelle',
       readinessBody: 'Les principaux workflows admin sont connectés et prêts pour le support plateforme.',
@@ -55,7 +55,7 @@ export default function AdminDashboardPage() {
         ['Locataires', 'Gérer les workflows de confiance, de blocage et de récupération.', 'Voir tout'],
         ['Journaux d’audit', 'Tracer chaque action admin sensible dans RentalDriveGo.', 'Voir les journaux'],
       ],
-      health: ['Comptes locataires', 'Identité marketplace', 'Piste d’audit admin'],
+      health: ['Comptes locataires', 'Identité storefront', 'Piste d’audit admin'],
     },
     ar: {
       kpis: ['إجمالي الشركات', 'الشركات النشطة', 'إجمالي المستأجرين', 'إجمالي الحجوزات'],