feat(admin): add comprehensive admin management system

- Add admin handlers and services for users, posts, comments, groups, and dashboard
- Implement role permission management with ability to view and update permissions
- Add database seeding for roles and Casbin permission policies
- Upgrade Casbin from v2 to v3 with GORM adapter for persistent policy storage
- Add admin-specific repository methods with filtering and pagination
- Register new admin API routes under /api/v1/admin/*

cmd/test_casbin/main.go

@@ -13,7 +13,8 @@ import (
 	"carrot_bbs/internal/repository"
 	"carrot_bbs/internal/service"
 
-	"github.com/casbin/casbin/v2"
+	"github.com/casbin/casbin/v3"
+	gormadapter "github.com/casbin/gorm-adapter/v3"
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
 )
@@ -64,8 +65,14 @@ func main() {
 		log.Printf("[WARNING] Failed to init casbin policies: %v", err)
 	}
 
+	// 创建 GORM 适配器
+	adapter, err := gormadapter.NewAdapterByDB(db)
+	if err != nil {
+		log.Fatalf("Failed to create GORM adapter: %v", err)
+	}
+
 	// 创建 Casbin Enforcer
-	enforcer, err := casbin.NewEnforcer(cfg.Casbin.ModelPath)
+	enforcer, err := casbin.NewEnforcer(cfg.Casbin.ModelPath, adapter)
 	if err != nil {
 		log.Fatalf("Failed to create enforcer: %v", err)
 	}