feat(web): add listing detail page and Mapbox GL JS map integration

- Create public listing detail page at /listings/[id] with image gallery,
  property specs, contact card, and embedded map
- Rewrite ListingMap component to use Mapbox GL JS with interactive markers,
  price labels, and listing popups
- Add selectedListingId prop to search page map views for marker highlighting
- Install mapbox-gl dependency

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/package.json

@@ -14,6 +14,7 @@
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-react": "^1.7.0",
+    "mapbox-gl": "^3.21.0",
     "next": "^14.2.0",
     "react": "^18.3.0",
     "react-dom": "^18.3.0",
@@ -23,6 +24,7 @@
     "zustand": "^5.0.12"
   },
   "devDependencies": {
+    "@types/mapbox-gl": "^3.5.0",
     "@types/node": "^22.0.0",
     "@types/react": "^18.3.0",
     "@types/react-dom": "^18.3.0",