wf reorg 4 demo workflow in example

docs/wf_core_architecture.md

@@ -64,8 +64,6 @@ raising at the first failure.
 
 ## What This Cleanup Does Not Solve Yet
 
-- `demo_workflow.py` is still large because it is a fixture/demo, not core
-  runtime. If it becomes a permanent example suite, move it out of `wf_core`.
 - Foreach is still serial-only. Parallel foreach needs an explicit scheduling
   model, not just `asyncio.gather`.
 - Interrupt lifecycle is still node-level and run-state-level. Long-lived

examples/__init__.py

@@ -0,0 +1 @@
+"""Runnable workflow examples for local development and tests."""

examples/demo_workflow.py

@@ -3,9 +3,7 @@ from __future__ import annotations
 from collections.abc import Callable
 from typing import cast
 
-from .models import Workflow
+from wf_core import END, RuntimeContext, Workflow
-from .run_state import RuntimeContext
-from .tokens import END
 
 DemoHandler = Callable[[dict[str, object], RuntimeContext], dict[str, object]]
 

main.py

@@ -2,7 +2,7 @@ import json
 import sys
 
 from wf_core import RunState, execute_workflow, resume_workflow
-from wf_core.demo_workflow import build_demo_registry, build_demo_workflow
+from examples.demo_workflow import build_demo_registry, build_demo_workflow
 
 
 def print_run(label: str, run: RunState) -> None:

tests/authoring/test_demo_workflow.py

@@ -11,8 +11,8 @@ from wf_core import (
     resume_workflow,
     step_workflow,
 )
-from wf_core.demo_workflow import build_demo_registry, build_demo_workflow
 from wf_core.runtime.ops.runs import create_run_state
+from examples.demo_workflow import build_demo_registry, build_demo_workflow
 from wf_authoring import (
     NodeReturn,
     WorkflowBuilder,

tests/authoring/test_subgraph.py

@@ -4,7 +4,7 @@ from pydantic import BaseModel
 
 from wf_authoring import build_registry, subgraph_node
 from wf_core import RuntimeContext
-from wf_core.demo_workflow import build_demo_registry, build_demo_workflow
+from examples.demo_workflow import build_demo_registry, build_demo_workflow
 
 
 def test_subgraph_node_wraps_compiled_workflow() -> None: