STATE-WP-0069 T06: add workplan flow entity and prefer open_workplans

Introduce flows/workplan.yaml and /flows/workplan/* routes alongside the
legacy workstream flow. Dashboard, README, and MCP flow docs now prefer
open_workplans with open_workstreams fallback until dual-key retirement.

tests/test_routers_core.py

@@ -507,7 +507,22 @@ class TestFlowEndpoints:
         r = await client.get("/flows/definitions")
         assert r.status_code == 200
         entity_types = {item["entity_type"] for item in r.json()}
-        assert {"workstream", "task", "contribution", "capability_request"} <= entity_types
+        assert {"workplan", "workstream", "task", "contribution", "capability_request"} <= entity_types
+
+    async def test_get_flow_state_and_advance_workplan(self, client):
+        await _create_domain(client)
+        topic = await _create_topic(client)
+        ws = await _create_workstream(client, topic["id"])
+        task = await _create_task(client, ws["id"])
+        await client.patch(f"/tasks/{task['id']}", json={"status": "done"})
+
+        r = await client.get(f"/flows/workplan/{ws['id']}")
+        assert r.status_code == 200
+        assert r.json()["current_workstation"] == "active"
+
+        r = await client.post(f"/flows/workplan/{ws['id']}/advance/finished")
+        assert r.status_code == 200
+        assert r.json()["current_workstation"] == "finished"
 
     async def test_get_flow_state_and_advance_workstream(self, client):
         await _create_domain(client)

tests/test_task_flow_engine.py

@@ -173,9 +173,27 @@ def test_yaml_flow_definitions_load_and_evaluate_representative_entities():
         "capability_request",
         "contribution",
         "task",
+        "workplan",
         "workstream",
     ]
 
+    workplan_result = FlowEngine(
+        custom_ops={
+            "dependencies.any_incomplete": lambda assertion, obj, values: any(
+                value not in assertion.value for value in values
+            )
+        }
+    ).evaluate(
+        {
+            "status": "active",
+            "tasks": [{"status": "done"}],
+            "dependencies": [{"workstation": "finished"}],
+        },
+        flows["workplan"],
+    )
+    assert "finished" in workplan_result.reachable
+    assert "blocked" in [item.workstation for item in workplan_result.unreachable]
+
     workstream_result = FlowEngine(
         custom_ops={
             "dependencies.any_incomplete": lambda assertion, obj, values: any(