Add nightlyRate in active room stays response

docs/API_REFERENCE.txt

@@ -1304,6 +1304,7 @@ ROOM STAYS + CARDS APIS
   What it does:
 
   - Returns active stays with booking and guest details.
+  - Includes per-stay nightlyRate (nullable when rate was not set on room stay).
   - AGENT-only users are blocked.
 
   Request body:

src/main/kotlin/com/android/trisolarisserver/controller/dto/room/RoomStayDtos.kt

@@ -13,5 +13,6 @@ data class ActiveRoomStayResponse(
     val roomTypeName: String,
     val fromAt: String,
     val checkinAt: String?,
-    val expectedCheckoutAt: String?
+    val expectedCheckoutAt: String?,
+    val nightlyRate: Long?
 )

src/main/kotlin/com/android/trisolarisserver/controller/room/RoomStays.kt

@@ -69,7 +69,8 @@ class RoomStays(
                 roomTypeName = roomType.name,
                 fromAt = stay.fromAt.toString(),
                 checkinAt = booking.checkinAt?.toString(),
-                expectedCheckoutAt = booking.expectedCheckoutAt?.toString()
+                expectedCheckoutAt = booking.expectedCheckoutAt?.toString(),
+                nightlyRate = stay.nightlyRate
             )
         }
     }