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/(public)/explore/[slug]/page.tsx

@@ -1,6 +1,6 @@
 import Link from 'next/link'
-import { marketplaceFetchOrDefault } from '@/lib/api'
-import { getMarketplaceLanguage } from '@/lib/i18n.server'
+import { storefrontFetchOrDefault } from '@/lib/api'
+import { getStorefrontLanguage } from '@/lib/i18n.server'
 import { formatCurrency } from '@rentaldrivego/types'
 
 interface CompanyProfile {
@@ -21,14 +21,14 @@ interface CompanyProfile {
 }
 
 export default async function CompanyProfilePage({ params }: { params: { slug: string } }) {
-  const language = await getMarketplaceLanguage()
+  const language = await getStorefrontLanguage()
   const dict = {
     en: {
-      unavailable: 'Marketplace unavailable',
+      unavailable: 'Storefront unavailable',
       unavailableTitle: 'Company details are temporarily unavailable.',
-      unavailableBody: 'The marketplace API is running, but the database is not reachable in this local environment.',
+      unavailableBody: 'The storefront API is running, but the database is not reachable in this local environment.',
       backToExplore: 'Back to explore',
-      partner: 'Marketplace partner',
+      partner: 'Storefront partner',
       vehicles: 'vehicles',
       offers: 'active offers',
       rating: 'Rating',
@@ -42,11 +42,11 @@ export default async function CompanyProfilePage({ params }: { params: { slug: s
       unavailableNoDate: 'Temporarily unavailable for new reservations.',
     },
     fr: {
-      unavailable: 'Marketplace indisponible',
+      unavailable: 'Storefront indisponible',
       unavailableTitle: "Les détails de l'entreprise sont temporairement indisponibles.",
-      unavailableBody: "L'API marketplace fonctionne, mais la base de données n'est pas accessible dans cet environnement local.",
+      unavailableBody: "L'API storefront fonctionne, mais la base de données n'est pas accessible dans cet environnement local.",
       backToExplore: "Retour à l'exploration",
-      partner: 'Partenaire marketplace',
+      partner: 'Partenaire storefront',
       vehicles: 'véhicules',
       offers: 'offres actives',
       rating: 'Note',
@@ -78,7 +78,7 @@ export default async function CompanyProfilePage({ params }: { params: { slug: s
       unavailableNoDate: 'غير متاحة مؤقتاً للحجوزات الجديدة.',
     },
   }[language]
-  const company = await marketplaceFetchOrDefault<CompanyProfile | null>(`/marketplace/${params.slug}`, null)
+  const company = await storefrontFetchOrDefault<CompanyProfile | null>(`/storefront/${params.slug}`, null)
 
   if (!company) {
     return (