refactor: удалён мёртвый legacy-код загрузки напрямую (/upload, /unzip-upload, _check_ext, _unzip, ALLOWED, константы фронта); загрузка только через ВМ (/api/upload_refs)

site/routes/__init__.py

@@ -3,7 +3,7 @@
 
 def register_routes(app):
     import config
-    from routes.upload_bp import upload_bp, contracts_upload_sink
+    from routes.upload_bp import contracts_upload_sink
     from routes.pipeline_bp import pipeline_bp
     from routes.api_bp import api_bp
     from routes.prompts_bp import prompts_bp
@@ -11,7 +11,6 @@ def register_routes(app):
     from routes.pages_bp import pages_bp
     from upload.backend.upload_refs import create_upload_refs_blueprint
 
-    app.register_blueprint(upload_bp)
     app.register_blueprint(pipeline_bp)
     app.register_blueprint(api_bp)
     app.register_blueprint(prompts_bp)