refactor(architecture): eliminate internal package and complete cordis single-owner model and repository migration

- Physically purged all legacy internal/ packages, centralized pkg/model/ and pkg/repository/
- Migrated domain models and database repositories into self-contained owner plugins (user, auth, message_gateway, admin, upload, risk_control)
- Decoupled cross-plugin interactions via pure core/contracts and typed EventBus
- Ensured 100% test coverage pass, zero data races (-race clean), and 0 lint issues in make code-check

plugins/domain/upload/storage/storage_ops.go

@@ -6,9 +6,9 @@ package storage
 import (
 	"context"
 
-	"github.com/Rain-kl/Wavelet/internal/infra/objectstore"
-	"github.com/Rain-kl/Wavelet/internal/model"
 	"github.com/Rain-kl/Wavelet/pkg/logger"
+	"github.com/Rain-kl/Wavelet/plugins/domain/upload/models"
+	"github.com/Rain-kl/Wavelet/plugins/infra/storage/objectstore"
 )
 
 // ReadOnly checks if the storage system is in read-only maintenance mode.
@@ -22,7 +22,7 @@ func ReadOnly(ctx context.Context) bool {
 }
 
 // OpenStoredObject opens a stored upload object from the active storage backend.
-func OpenStoredObject(ctx context.Context, upload *model.Upload) (*objectstore.Object, error) {
+func OpenStoredObject(ctx context.Context, upload *models.Upload) (*objectstore.Object, error) {
 	_, backend, err := objectstore.Active(ctx)
 	if err != nil {
 		return nil, err