feat(subscription): validate price amount and migrate database column type

- Add validation to ensure subscription plan price amount is non-negative and does not exceed 9999.
- Migrate the price_amount column from float/double to decimal(10,6) in the database for improved precision.
- Update SubscriptionPlan model to reflect the new decimal type for price_amount.

controller/subscription.go

@@ -118,6 +118,14 @@ func AdminCreateSubscriptionPlan(c *gin.Context) {
 		common.ApiErrorMsg(c, "套餐标题不能为空")
 		return
 	}
+	if req.Plan.PriceAmount < 0 {
+		common.ApiErrorMsg(c, "价格不能为负数")
+		return
+	}
+	if req.Plan.PriceAmount > 9999 {
+		common.ApiErrorMsg(c, "价格不能超过9999")
+		return
+	}
 	if req.Plan.Currency == "" {
 		req.Plan.Currency = "USD"
 	}
@@ -172,6 +180,14 @@ func AdminUpdateSubscriptionPlan(c *gin.Context) {
 		common.ApiErrorMsg(c, "套餐标题不能为空")
 		return
 	}
+	if req.Plan.PriceAmount < 0 {
+		common.ApiErrorMsg(c, "价格不能为负数")
+		return
+	}
+	if req.Plan.PriceAmount > 9999 {
+		common.ApiErrorMsg(c, "价格不能超过9999")
+		return
+	}
 	req.Plan.Id = id
 	if req.Plan.Currency == "" {
 		req.Plan.Currency = "USD"