Python: Add declarative workflow runtime (#2815)

* Further support for declarative python workflows

* Add tests. Clean up for typing and formatting

* Improvements and cleanup

* Typing cleanup. Improve docstrings

* Proper code in docstrings

* Fix malformed code-block directive in docstring

* Remove dead links

* PR feedback

* Address PR feedback

* Address PR feedback

* Remove sl

* Update devui frontend

* More cleanup

* Fix uv lock

* Skip Py 3.14 tests as powerfx doesn't support it

* Fix mypy error

* Fix for tool calls

* Removed stale docstring

* Fix lint

* Standardize on .NET namespaces. Revert DevUI changes (bring in later)

* Implement remaining items for Python declarative support to match dotnet

python/samples/getting_started/devui/declarative/workflow.py

@@ -0,0 +1,25 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""
+Run the declarative workflow sample with DevUI.
+
+Demonstrates conditional branching based on age input using YAML-defined workflow.
+"""
+
+from pathlib import Path
+
+from agent_framework.declarative import WorkflowFactory
+from agent_framework.devui import serve
+
+factory = WorkflowFactory()
+workflow_path = Path(__file__).parent / "workflow.yaml"
+workflow = factory.create_workflow_from_yaml_path(workflow_path)
+
+
+def main():
+    """Run the declarative workflow with DevUI."""
+    serve(entities=[workflow], auto_open=True)
+
+
+if __name__ == "__main__":
+    main()