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

services/city-service/routes_city.py

@@ -1048,6 +1048,81 @@ async def create_city_room(payload: CityRoomCreate):
         raise HTTPException(status_code=500, detail="Failed to create city room")
 
 
+@api_router.get("/city/rooms")
+async def get_city_rooms_api():
+    """
+    Отримати список всіх City Rooms для API.
+    """
+    try:
+        rooms = await repo_city.get_all_rooms(limit=100, offset=0)
+        
+        result = []
+        for room in rooms:
+            result.append({
+                "id": room.get("id"),
+                "slug": room.get("slug"),
+                "name": room.get("name"),
+                "description": room.get("description"),
+                "scope": room.get("owner_type", "city"),
+                "matrix_room_id": room.get("matrix_room_id"),
+                "is_public": room.get("is_public", True),
+                "room_role": room.get("room_role"),
+            })
+        
+        return result
+    except Exception as e:
+        logger.error(f"Failed to get city rooms: {e}")
+        raise HTTPException(status_code=500, detail="Failed to get city rooms")
+
+
+@api_router.get("/city/rooms/{slug}")
+async def get_city_room_by_slug(slug: str):
+    """
+    Отримати деталі City Room за slug.
+    """
+    try:
+        room = await repo_city.get_room_by_slug(slug)
+        if not room:
+            raise HTTPException(status_code=404, detail=f"Room not found: {slug}")
+        
+        # Get host agents for this room (public agents assigned to city rooms)
+        host_agents = []
+        try:
+            # Get DARIO and DARIA as default hosts for city rooms
+            default_hosts = ["dario", "daria", "daarwizz"]
+            for agent_id in default_hosts:
+                agent = await repo_city.get_agent_by_id(agent_id)
+                if agent:
+                    host_agents.append({
+                        "id": agent.get("id"),
+                        "display_name": agent.get("display_name"),
+                        "avatar_url": agent.get("avatar_url"),
+                        "kind": agent.get("kind"),
+                        "role": "host"
+                    })
+        except Exception as e:
+            logger.warning(f"Failed to get host agents for room {slug}: {e}")
+        
+        return {
+            "id": room.get("id"),
+            "slug": room.get("slug"),
+            "name": room.get("name"),
+            "description": room.get("description"),
+            "scope": room.get("owner_type", "city"),
+            "matrix_room_id": room.get("matrix_room_id"),
+            "matrix_room_alias": room.get("matrix_room_alias"),
+            "is_public": room.get("is_public", True),
+            "room_role": room.get("room_role"),
+            "host_agents": host_agents,
+            "chat_available": room.get("matrix_room_id") is not None
+        }
+    except HTTPException:
+        raise
+    except Exception as e:
+        logger.error(f"Failed to get city room by slug {slug}: {e}")
+        raise HTTPException(status_code=500, detail="Failed to get city room")
+
+
 @router.get("/rooms/{room_id}", response_model=CityRoomDetail)
 async def get_city_room(room_id: str):
     """