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>

internal/types/lottery.go

@@ -261,9 +261,10 @@ type CreateAdminLotteryPrizeRequest struct {
 	IsFallback bool            `json:"is_fallback"`
 }
 
-// UpdateAdminLotteryPrizeRequest updates mutable prize fields.
+// UpdateAdminLotteryPrizeRequest updates mutable prize fields. Id comes from
+// the URL path (PUT /prizes/:id), not the body.
 type UpdateAdminLotteryPrizeRequest struct {
-	Id         int64           `json:"id" validate:"required"`
+	Id         int64           `path:"id" json:"-" validate:"required"`
 	Slot       *int            `json:"slot,omitempty"`
 	Name       string          `json:"name,omitempty"`
 	IconUrl    string          `json:"icon_url,omitempty"`
@@ -283,9 +284,9 @@ type ListAdminLotteryPrizesResponse struct {
 	List []AdminLotteryPrize `json:"list"`
 }
 
-// AdminPrizeIdRequest is used by DELETE / GET single.
+// AdminPrizeIdRequest is used by DELETE /prizes/:id. Id comes from the URL path.
 type AdminPrizeIdRequest struct {
-	Id int64 `form:"id" json:"id" validate:"required"`
+	Id int64 `path:"id" form:"id" json:"id" validate:"required"`
 }
 
 // GrantAdminLotteryChanceRequest gives a specified user N chances on an