feat: 迁移预警规则管理和历史分类查询

internal/data/business/migrations.go

@@ -6,7 +6,7 @@ import (
 )
 
 func Migrations() []migration.Step {
-	return []migration.Step{{ID: "202611030005_business_password_reset", Migrate: func(db *gorm.DB) error {
+	return []migration.Step{{ID: "202611030006_business_alert_schema", Migrate: migrateAlertSchema}, {ID: "202611030005_business_password_reset", Migrate: func(db *gorm.DB) error {
 		return migration.CreateMissingTables(db, &resetCodePO{}, &resetTokenPO{})
 	}}, {ID: "202611030004_business_binding_locks", Migrate: func(db *gorm.DB) error {
 		return migration.CreateMissingTables(db, &bindingLockPO{})
@@ -35,3 +35,27 @@ func Migrations() []migration.Step {
 		})
 	}}}
 }
+
+func migrateAlertSchema(db *gorm.DB) error {
+	if err := migration.CreateMissingTables(db, &alertRulePO{}, &alertRecordPO{}, &alertLogPO{}); err != nil {
+		return err
+	}
+	if db.Dialector.Name() != "mysql" {
+		return nil
+	}
+	columns, err := db.Migrator().ColumnTypes(&alertRulePO{})
+	if err != nil {
+		return err
+	}
+	for _, column := range columns {
+		if column.Name() == "mom_threshold" {
+			precision, scale, ok := column.DecimalSize()
+			if ok && precision >= 7 && scale >= 2 {
+				return nil
+			}
+			// 原页面允许 9999%，旧 decimal(5,2) 装不下；扩大精度且不改变已有值。
+			return db.Migrator().AlterColumn(&alertRulePO{}, "MomThreshold")
+		}
+	}
+	return nil
+}