重构(#4): 抽奖奖品改/删 id 走 URL path（RESTful）

- PUT /admin/lottery/prizes/:id、DELETE /admin/lottery/prizes/:id
- handler 从 c.Param("id") 取 id；types 用 path:"id"
- 同步 apis/admin/lottery.api 定义

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apis/admin/lottery.api

@@ -49,11 +49,11 @@ service ppanel {
 
 	@doc "Update prize"
 	@handler UpdateLotteryPrize
-	put /prizes (UpdateAdminLotteryPrizeRequest) returns (AdminLotteryPrize)
+	put /prizes/:id (UpdateAdminLotteryPrizeRequest) returns (AdminLotteryPrize)
 
 	@doc "Delete prize"
 	@handler DeleteLotteryPrize
-	delete /prizes (AdminPrizeIdRequest)
+	delete /prizes/:id (AdminPrizeIdRequest)
 
 	@doc "List prizes on an activity"
 	@handler ListLotteryPrizes