Rename legacy storefront app and references to carplace

Replace storefront naming across source, tests, docs, config, and production scripts. Rename the legacy top-level app directory and Carplace component files, remove duplicate storefront startup scripts, and refresh the lockfile.

PHASE16_DESIGN_MIGRATION_MANIFEST.json

@@ -11,7 +11,7 @@
     "homepage": "retained as embedded Phase 16 source of truth",
     "admin": "migrated",
     "dashboard": "migrated",
-    "storefront": "migrated",
+    "carplace": "migrated",
     "api": "unchanged"
   },
   "validation": {
@@ -37,37 +37,37 @@
       "sha256": "7a35fad2750bccc09c24f24c1d57594048b040f24d4cde7639fa1a2ce3d63e64"
     },
     {
-      "path": "storefront/src/app/layout.tsx",
+      "path": "carplace/src/app/layout.tsx",
       "status": "modified",
       "bytes": 1833,
       "sha256": "6fed4ef50a886e1c551b6456b46c5fc785b02a4be988aef06fa95c28443bbd27"
     },
     {
-      "path": "storefront/src/app/globals.css",
+      "path": "carplace/src/app/globals.css",
       "status": "modified",
       "bytes": 7525,
       "sha256": "49e03206558248eb5de2b9a8463be6e0b43e01df518bc0b625fe2953a18185c6"
     },
     {
-      "path": "storefront/src/components/StorefrontFooter.tsx",
+      "path": "carplace/src/components/CarplaceFooter.tsx",
       "status": "modified",
       "bytes": 4632,
       "sha256": "169d04dcf0976d2637ef5371ca295e9c362bd089d8d6ec313b4e8b4131d5bdd3"
     },
     {
-      "path": "storefront/src/components/StorefrontHeader.tsx",
+      "path": "carplace/src/components/CarplaceHeader.tsx",
       "status": "modified",
       "bytes": 10438,
       "sha256": "25afc57ff9893f255eddf19580e84b510e6032764daaa5727e2e8d669dca4213"
     },
     {
-      "path": "storefront/src/styles/phase16-tokens.css",
+      "path": "carplace/src/styles/phase16-tokens.css",
       "status": "added",
       "bytes": 4214,
       "sha256": "0e7fb35fb2833ff564c1188e39735349a8df901938fa87f2dc1b931dd4f04cd0"
     },
     {
-      "path": "storefront/src/app/(public)/explore/[slug]/vehicles/[id]/page.tsx",
+      "path": "carplace/src/app/(public)/explore/[slug]/vehicles/[id]/page.tsx",
       "status": "modified",
       "bytes": 13979,
       "sha256": "9edf8da13e50cabcb2a126b300c71cb0b7a096a31d11d364e37dc09eeb625d3b"