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

storefront/src/app/renter/profile/page.tsx

@@ -12,7 +12,7 @@ import {
   type RenterPreference,
   type RenterProfile,
 } from '@/lib/renter'
-import { useMarketplacePreferences } from '@/components/MarketplaceShell'
+import { useStorefrontPreferences } from '@/components/StorefrontShell'
 
 type Status = 'loading' | 'ready' | 'error'
 const RENTER_EVENTS = ['BOOKING_CONFIRMED', 'BOOKING_REMINDER', 'RETURN_REMINDER', 'REFUND_ISSUED', 'NEW_OFFER']
@@ -20,7 +20,7 @@ const RENTER_CHANNELS = ['EMAIL', 'SMS', 'WHATSAPP', 'PUSH', 'IN_APP']
 
 export default function RenterProfilePage() {
   const router = useRouter()
-  const { language } = useMarketplacePreferences()
+  const { language } = useStorefrontPreferences()
   const dict = {
     en: {
       profile: 'Profile',