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/tests/unit_tests/controllers/console/app/workflow_draft_variables_test.py

@@ -310,8 +310,8 @@ def test_workflow_node_variables_fields():
 
 def test_workflow_file_variable_with_signed_url():
     """Test that File type variables include signed URLs in API responses."""
-    from core.file.enums import FileTransferMethod, FileType
-    from core.file.models import File
+    from core.workflow.file.enums import FileTransferMethod, FileType
+    from core.workflow.file.models import File
 
     # Create a File object with LOCAL_FILE transfer method (which generates signed URLs)
     test_file = File(
@@ -368,8 +368,8 @@ def test_workflow_file_variable_with_signed_url():
 
 def test_workflow_file_variable_remote_url():
     """Test that File type variables with REMOTE_URL transfer method return the remote URL."""
-    from core.file.enums import FileTransferMethod, FileType
-    from core.file.models import File
+    from core.workflow.file.enums import FileTransferMethod, FileType
+    from core.workflow.file.models import File
 
     # Create a File object with REMOTE_URL transfer method
     test_file = File(

api/tests/unit_tests/controllers/console/datasets/test_datasets_document_download.py

@@ -49,8 +49,8 @@ def datasets_document_module(monkeypatch: pytest.MonkeyPatch):
     monkeypatch.setattr(wraps, "account_initialization_required", _noop)
 
     # Bypass billing-related decorators used by other endpoints in this module.
-    monkeypatch.setattr(wraps, "cloud_edition_billing_resource_check", lambda *_args, **_kwargs: (lambda f: f))
-    monkeypatch.setattr(wraps, "cloud_edition_billing_rate_limit_check", lambda *_args, **_kwargs: (lambda f: f))
+    monkeypatch.setattr(wraps, "cloud_edition_billing_resource_check", lambda *_args, **_kwargs: lambda f: f)
+    monkeypatch.setattr(wraps, "cloud_edition_billing_rate_limit_check", lambda *_args, **_kwargs: lambda f: f)
 
     # Avoid Flask-RESTX route registration side effects during import.
     def _noop_route(*_args, **_kwargs):  # type: ignore[override]