refactor: reorganize models to pkg/model and add authentication module

- Move ORM models from internal/model to pkg/model organized by module (auth/k8s/registry)
- Add authentication module with login, user management handlers
- Update all import paths to use new model locations
- Add frontend auth pages (Login, UserManagement) and authStore
- Remove deprecated internal/model/model.go

internal/module/registry/catalog.go

@@ -4,7 +4,7 @@ import (
 	"strconv"
 	"strings"
 
-	"gitea.loveuer.com/loveuer/cluster/internal/model"
+	"gitea.loveuer.com/loveuer/cluster/pkg/model/registry"
 	"gitea.loveuer.com/loveuer/cluster/pkg/resp"
 	"gitea.loveuer.com/loveuer/cluster/pkg/store"
 	"github.com/gofiber/fiber/v3"
@@ -31,7 +31,7 @@ func HandleCatalog(c fiber.Ctx, db *gorm.DB, store store.Store) error {
 	last := c.Query("last")
 
 	// ????
-	var repos []model.Repository
+	var repos []registry.Repository
 	query := db.Order("name ASC").Limit(n + 1)
 
 	if last != "" {