fix: guard RefererId and monetary fields against zero-value overwrite in updateUserBasicInfo

- Change RefererId, Balance, GiftAmount, Commission from int64 to *int64 in UpdateUserBasiceInfoRequest
- When field is nil (not sent by client), skip update entirely — prevents zero-value from clobbering existing data
- When field is non-nil, dereference and apply as before (including explicit 0 to clear a value)
- Mirrors the existing guard pattern already used for Avatar, ReferCode, Enable, IsAdmin, etc.

Fixes: RefererId unconditional overwrite at line 123 (P02)
Fixes: Balance/GiftAmount/Commission triggering adjustment to 0 when omitted (P03)
Co-authored-by: multica-agent <github@multica.ai>

apis/admin/user.api

@@ -38,20 +38,20 @@ type (
 		Id int64 `form:"id" validate:"required"`
 	}
 	UpdateUserBasiceInfoRequest {
-		UserId             int64  `json:"user_id" validate:"required"`
-		Password           string `json:"password"`
-		Avatar             string `json:"avatar"`
-		Balance            int64  `json:"balance"`
-		Commission         int64  `json:"commission"`
-		ReferralPercentage uint8  `json:"referral_percentage"`
-		OnlyFirstPurchase  *bool  `json:"only_first_purchase"`
-		GiftAmount         int64  `json:"gift_amount"`
-		Telegram           int64  `json:"telegram"`
-		ReferCode          string `json:"refer_code"`
-		RefererId          int64  `json:"referer_id"`
-		Enable             *bool  `json:"enable"`
-		IsAdmin            *bool  `json:"is_admin"`
-		Remark             string `json:"remark"`
+		UserId             int64   `json:"user_id" validate:"required"`
+		Password           string  `json:"password"`
+		Avatar             string  `json:"avatar"`
+		Balance            *int64  `json:"balance"`
+		Commission         *int64  `json:"commission"`
+		ReferralPercentage uint8   `json:"referral_percentage"`
+		OnlyFirstPurchase  *bool   `json:"only_first_purchase"`
+		GiftAmount         *int64  `json:"gift_amount"`
+		Telegram           int64   `json:"telegram"`
+		ReferCode          string  `json:"refer_code"`
+		RefererId          *int64  `json:"referer_id"`
+		Enable             *bool   `json:"enable"`
+		IsAdmin            *bool   `json:"is_admin"`
+		Remark             string  `json:"remark"`
 	}
 	UpdateUserNotifySettingRequest {
 		UserId                int64 `json:"user_id" validate:"required"`