Python: [Breaking] Remove WorkflowCompletedEvent, introduce workflow output and migrate to ctx.yield_output() + a huge refactoring (#845)

* Introduce input and output types for executor and workflow

* WorkflowOutputContext handles two types

* Remove can_handle_types from Executor

* Update validation

* Move workflow executor

* Move workflow executor

* Fix issues in WorkflowExecutor

* refactor executor

* update execute signature to create workflow context within Executor

* fix simple sub workflow test; fix validation

* fix output types in WorkflowExecutor

* fix issue in Executor handling of SubWorkflowRequestInfo

* update tests to use proper workflow output

* update orchestration patterns to use output

* Update sample -- not finished

* Update python/packages/main/tests/workflow/test_workflow_states.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update python/packages/main/tests/workflow/test_concurrent.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* address comments

* WorkflowOutputContext --> WorkflowContext

* remove WorkflowCompletedEvent

* update samples

* Update doc string for important classes; update WorkflowExecutor to support concurrent execution

* use Never instead of None for default type

* Update usage of WorkflowContext[None to WorkflowContext[Never

* address comments

* remove filter for None

* address comments, minor fixes

* quality of life improvement on interceptor types

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

python/packages/main/tests/workflow/test_runner.py

@@ -9,10 +9,11 @@ from agent_framework import (
     AgentExecutorResponse,
     AgentRunResponse,
     Executor,
-    WorkflowCompletedEvent,
     WorkflowContext,
     WorkflowEvent,
-    WorkflowEventSource,
+    WorkflowOutputEvent,
+    WorkflowRunState,
+    WorkflowStatusEvent,
     handler,
 )
 from agent_framework._workflow._edge import SingleEdgeGroup
@@ -32,11 +33,12 @@ class MockExecutor(Executor):
     """A mock executor for testing purposes."""
 
     @handler
-    async def mock_handler(self, message: MockMessage, ctx: WorkflowContext[MockMessage]) -> None:
+    async def mock_handler(self, message: MockMessage, ctx: WorkflowContext[MockMessage, int]) -> None:
         if message.data < 10:
             await ctx.send_message(MockMessage(data=message.data + 1))
         else:
-            await ctx.add_event(WorkflowCompletedEvent(data=message.data))
+            await ctx.yield_output(message.data)
+            pass
 
 
 def test_create_runner():
@@ -77,18 +79,14 @@ async def test_runner_run_until_convergence():
     result: int | None = None
     await executor_a.execute(
         MockMessage(data=0),
-        WorkflowContext(
-            executor_id=executor_a.id,
-            source_executor_ids=["START"],
-            shared_state=shared_state,
-            runner_context=ctx,
-        ),
+        ["START"],  # source_executor_ids
+        shared_state,  # shared_state
+        ctx,  # runner_context
     )
     async for event in runner.run_until_convergence():
         assert isinstance(event, WorkflowEvent)
-        if isinstance(event, WorkflowCompletedEvent):
+        if isinstance(event, WorkflowOutputEvent):
             result = event.data
-            assert event.origin is WorkflowEventSource.EXECUTOR
 
     assert result is not None and result == 10
 
@@ -112,16 +110,13 @@ async def test_runner_run_until_convergence_not_completed():
 
     await executor_a.execute(
         MockMessage(data=0),
-        WorkflowContext(
-            executor_id=executor_a.id,
-            source_executor_ids=["START"],
-            shared_state=shared_state,
-            runner_context=ctx,
-        ),
+        ["START"],  # source_executor_ids
+        shared_state,  # shared_state
+        ctx,  # runner_context
     )
     with pytest.raises(RuntimeError, match="Runner did not converge after 5 iterations."):
         async for event in runner.run_until_convergence():
-            assert not isinstance(event, WorkflowCompletedEvent)
+            assert not isinstance(event, WorkflowStatusEvent) or event.state != WorkflowRunState.IDLE
 
 
 async def test_runner_already_running():
@@ -143,12 +138,9 @@ async def test_runner_already_running():
 
     await executor_a.execute(
         MockMessage(data=0),
-        WorkflowContext(
-            executor_id=executor_a.id,
-            source_executor_ids=["START"],
-            shared_state=shared_state,
-            runner_context=ctx,
-        ),
+        ["START"],  # source_executor_ids
+        shared_state,  # shared_state
+        ctx,  # runner_context
     )
 
     with pytest.raises(RuntimeError, match="Runner is already running."):
@@ -172,6 +164,6 @@ async def test_runner_emits_runner_completion_for_agent_response_without_targets
     )
 
     events: list[WorkflowEvent] = [event async for event in runner.run_until_convergence()]
-    completions = [e for e in events if isinstance(e, WorkflowCompletedEvent)]
-    assert completions
-    assert all(e.origin is WorkflowEventSource.FRAMEWORK for e in completions)
+    # The runner should complete without errors when handling AgentExecutorResponse without targets
+    # No specific events are expected since there are no executors to process the message
+    assert isinstance(events, list)  # Just verify the runner completed without errors