feat: add retention policy and stability verification

internal/config/config.go

@@ -7,9 +7,12 @@ import (
 	"os"
 	"strconv"
 	"time"
+
+	"git.yuntuo.hk/k2safe/orbit/internal/retention"
 )
 
 type Config struct {
+	RetentionDefaults     retention.Policy // RetentionDefaults 未保存数据库策略时使用的部署默认值。
 	HTTPAddr              string
 	MySQLDSN              string
 	MaxOpen               int
@@ -120,5 +123,10 @@ func FromEnv(get func(string) string) (Config, error) {
 			return Config{}, errors.New("invalid ORBIT_METRICS_ADDR")
 		}
 	}
+	var err error
+	c.RetentionDefaults, err = retention.FromEnv(get)
+	if err != nil {
+		return Config{}, err
+	}
 	return c, nil
 }