feat: Enhance texture upload functionality and API response format

- Introduced a new upload endpoint for direct texture file uploads, allowing users to upload textures with validation for size and format.
- Updated existing texture-related API responses to a standardized format, improving consistency across the application.
- Refactored texture service methods to handle file uploads and reuse existing texture URLs based on hash checks.
- Cleaned up Dockerfile and other files by removing unnecessary whitespace.

internal/repository/texture_repository.go

@@ -33,6 +33,12 @@ func (r *textureRepository) FindByHash(ctx context.Context, hash string) (*model
 	return handleNotFoundResult(&texture, err)
 }
 
+func (r *textureRepository) FindByHashAndUploaderID(ctx context.Context, hash string, uploaderID int64) (*model.Texture, error) {
+	var texture model.Texture
+	err := r.db.WithContext(ctx).Where("hash = ? AND uploader_id = ?", hash, uploaderID).First(&texture).Error
+	return handleNotFoundResult(&texture, err)
+}
+
 func (r *textureRepository) FindByIDs(ctx context.Context, ids []int64) ([]*model.Texture, error) {
 	if len(ids) == 0 {
 		return []*model.Texture{}, nil