fix: admin 初始化在数据库未就绪时静默失败

initAdmin 改为后台 goroutine 并重试最多 30 秒，避免 users-rpc
启动时 PostgreSQL 尚未接受连接导致管理员账户创建失败。

app/users/rpc/admin_init.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"os"
 	"strings"
+	"time"
 
 	"juwan-backend/app/snowflake/rpc/snowflake"
 	"juwan-backend/app/users/rpc/internal/models/users"
@@ -21,11 +22,23 @@ func initAdmin(svcCtx *svc.ServiceContext) {
 		return
 	}
 
+	go func() {
 		ctx := context.Background()
-	exists, _ := svcCtx.UsersModelRW.Users.Query().Where(users.UsernameEQ(username)).Exist(ctx)
+		for i := range 30 {
+			exists, err := svcCtx.UsersModelRW.Users.Query().Where(users.UsernameEQ(username)).Exist(ctx)
+			if err != nil {
+				if i < 29 {
+					time.Sleep(time.Second)
+					continue
+				}
+				logx.Errorf("check admin user: %v", err)
+				return
+			}
 			if exists {
 				return
 			}
+			break
+		}
 
 		hashedPassword, err := pwdUtils.HashPassword(password)
 		if err != nil {
@@ -57,4 +70,5 @@ func initAdmin(svcCtx *svc.ServiceContext) {
 		}
 
 		logx.Infof("initialized admin user: %s", username)
+	}()
 }