feat: City Rooms routing implementation

Backend:
- GET /api/v1/city/rooms - list all city rooms
- GET /api/v1/city/rooms/{slug} - get room by slug with host agents

Frontend:
- Updated /city/[slug] page with host agents section
- Added breadcrumb navigation
- Updated API client to fetch room by slug
- Added rewrite for /api/city/rooms/:slug

Task doc: TASK_PHASE_CITY_ROOMS_ROUTING_v1.md

apps/web/next.config.ts

@@ -36,6 +36,11 @@ const nextConfig: NextConfig = {
         source: '/api/public/:path*',
         destination: `${internalApiUrl}/public/:path*`,
       },
+      // City Rooms API (specific slug endpoint) -> /api/v1/city/rooms
+      {
+        source: '/api/city/rooms/:slug',
+        destination: `${internalApiUrl}/api/v1/city/rooms/:slug`,
+      },
       // City API -> /city
       {
         source: '/api/city/:path*',