fix: resolve import migrations and test failures after segment 3 merge

- Migrate core.model_runtime -> dify_graph.model_runtime across 20+ files
- Migrate core.workflow.file -> dify_graph.file across 15+ files
- Migrate core.workflow.enums -> dify_graph.enums in service files
- Fix SandboxContext phantom import in dify_graph/context/__init__.py
- Fix core.app.workflow.node_factory -> core.workflow.node_factory
- Fix toast import paths (useToastContext from toast/context)
- Fix app-info.tsx import paths for relocated app-operations
- Fix 15 frontend test files for API changes, missing QueryClientProvider,
  i18n key renames, and component behavior changes

Made-with: Cursor

api/controllers/console/workspace/account.py

@@ -37,7 +37,7 @@ from controllers.console.wraps import (
     only_edition_cloud,
     setup_required,
 )
-from core.workflow.file import helpers as file_helpers
+from dify_graph.file import helpers as file_helpers
 from extensions.ext_database import db
 from fields.member_fields import Account as AccountResponse
 from libs.datetime_utils import naive_utc_now

api/controllers/console/workspace/sandbox_providers.py

@@ -1,6 +1,6 @@
 import logging
 
-from core.model_runtime.utils.encoders import jsonable_encoder
+from dify_graph.model_runtime.utils.encoders import jsonable_encoder
 from flask import request
 from flask_restx import Resource, fields
 from pydantic import BaseModel