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

scripts/docker-prod-run-pulled-image.sh

@@ -90,7 +90,7 @@ echo "Applying migrations"
 prod_compose run --rm migrate
 
 echo "Starting application services"
-app_services=(api marketplace dashboard admin)
+app_services=(api storefront dashboard admin)
 
 if [[ "${INCLUDE_PGMANAGE}" == "1" ]]; then
   prod_compose --profile private-tools up -d "${app_services[@]}" pgmanage
@@ -98,7 +98,7 @@ else
   prod_compose up -d "${app_services[@]}"
 fi
 wait_for_healthy api 180
-wait_for_healthy marketplace 180
+wait_for_healthy storefront 180
 wait_for_healthy dashboard 180
 wait_for_healthy admin 180