refactor(workflow-file): phase2 replace remaining imports and remove core.file

Complete phase 2 of the file module migration by replacing the remaining repository-wide legacy imports and deleting the temporary core.file compatibility package introduced in phase 1.

What this commit changes
- Replace legacy core.file.* imports with core.workflow.file.* across:
  - controllers
  - core app/agent/datasource/prompt/rag/tools/variables
  - factories, fields, libs, models, services
  - otel parser integration points
  - unit and integration tests that referenced legacy paths
- Migrate residual runtime usages in app/task pipeline paths that still referenced core.file symbols.
- Update tests and model serialization helpers that relied on old module paths.
- Remove the compatibility bridge package entirely:
  - delete core/file/__init__.py
  - delete core/file/constants.py
  - delete core/file/enums.py
  - delete core/file/file_manager.py
  - delete core/file/helpers.py
  - delete core/file/models.py
  - delete core/file/tool_file_parser.py

Verification
- No Python references to core.file remain ( -> empty).
- Targeted regression tests for migrated file primitives and factory/type flows passed:
  - tests/unit_tests/core/test_file.py
  - tests/unit_tests/factories/test_variable_factory.py
  - tests/unit_tests/services/test_variable_truncator.py

Result
- The repository now uses core.workflow.file as the single canonical file namespace.
- The migration is fully split into two commits: phase 1 compatibility + phase 2 full cutover.

api/core/app/apps/base_app_generator.py

@@ -5,8 +5,8 @@ from sqlalchemy.orm import Session
 
 from core.app.app_config.entities import VariableEntityType
 from core.app.entities.app_invoke_entities import InvokeFrom
-from core.file import File, FileUploadConfig
 from core.workflow.enums import NodeType
+from core.workflow.file import File, FileUploadConfig
 from core.workflow.repositories.draft_variable_repository import (
     DraftVariableSaver,
     DraftVariableSaverFactory,

api/core/app/apps/base_app_runner.py

@@ -22,7 +22,6 @@ from core.app.entities.queue_entities import (
 from core.app.features.annotation_reply.annotation_reply import AnnotationReplyFeature
 from core.app.features.hosting_moderation.hosting_moderation import HostingModerationFeature
 from core.external_data_tool.external_data_fetch import ExternalDataFetch
-from core.file.enums import FileTransferMethod, FileType
 from core.memory.token_buffer_memory import TokenBufferMemory
 from core.model_manager import ModelInstance
 from core.model_runtime.entities.llm_entities import LLMResult, LLMResultChunk, LLMResultChunkDelta, LLMUsage
@@ -39,12 +38,13 @@ from core.prompt.advanced_prompt_transform import AdvancedPromptTransform
 from core.prompt.entities.advanced_prompt_entities import ChatModelMessage, CompletionModelPromptTemplate, MemoryConfig
 from core.prompt.simple_prompt_transform import ModelMode, SimplePromptTransform
 from core.tools.tool_file_manager import ToolFileManager
+from core.workflow.file.enums import FileTransferMethod, FileType
 from extensions.ext_database import db
 from models.enums import CreatorUserRole
 from models.model import App, AppMode, Message, MessageAnnotation, MessageFile
 
 if TYPE_CHECKING:
-    from core.file.models import File
+    from core.workflow.file.models import File
 
 _logger = logging.getLogger(__name__)
 

api/core/app/apps/chat/app_runner.py

@@ -11,12 +11,12 @@ from core.app.entities.app_invoke_entities import (
 )
 from core.app.entities.queue_entities import QueueAnnotationReplyEvent
 from core.callback_handler.index_tool_callback_handler import DatasetIndexToolCallbackHandler
-from core.file import File
 from core.memory.token_buffer_memory import TokenBufferMemory
 from core.model_manager import ModelInstance
 from core.model_runtime.entities.message_entities import ImagePromptMessageContent
 from core.moderation.base import ModerationError
 from core.rag.retrieval.dataset_retrieval import DatasetRetrieval
+from core.workflow.file import File
 from extensions.ext_database import db
 from models.model import App, Conversation, Message
 

api/core/app/apps/common/workflow_response_converter.py

@@ -45,7 +45,6 @@ from core.app.entities.task_entities import (
     WorkflowPauseStreamResponse,
     WorkflowStartStreamResponse,
 )
-from core.file import FILE_MODEL_IDENTITY, File
 from core.plugin.impl.datasource import PluginDatasourceManager
 from core.tools.entities.tool_entities import ToolProviderType
 from core.tools.tool_manager import ToolManager
@@ -60,6 +59,7 @@ from core.workflow.enums import (
     WorkflowNodeExecutionMetadataKey,
     WorkflowNodeExecutionStatus,
 )
+from core.workflow.file import FILE_MODEL_IDENTITY, File
 from core.workflow.runtime import GraphRuntimeState
 from core.workflow.system_variable import SystemVariable
 from core.workflow.workflow_entry import WorkflowEntry

api/core/app/apps/completion/app_runner.py

@@ -10,11 +10,11 @@ from core.app.entities.app_invoke_entities import (
     CompletionAppGenerateEntity,
 )
 from core.callback_handler.index_tool_callback_handler import DatasetIndexToolCallbackHandler
-from core.file import File
 from core.model_manager import ModelInstance
 from core.model_runtime.entities.message_entities import ImagePromptMessageContent
 from core.moderation.base import ModerationError
 from core.rag.retrieval.dataset_retrieval import DatasetRetrieval
+from core.workflow.file import File
 from extensions.ext_database import db
 from models.model import App, Message