feat(api): retire phase-1/2 /workstreams REST aliases with 410 stranglers

Add retire_legacy_route() helper and convert CRUD, dependency, and
execution intent legacy routes to 410 Gone while preserving final-call
legacy-meter attribution. Update tests, retirement backlog, and close
STATE-WP-0075 with handoff to STATE-WP-0070 T02 and STATE-WP-0073 T04.

tests/test_legacy_meter.py

@@ -67,7 +67,7 @@ class TestWorkplanAliasesAndLegacyMeter:
         assert r.status_code == 200
         assert r.json()["interfaces"] == []
 
-    async def test_legacy_workstream_route_is_metered_with_identity_buckets(self, client):
+    async def test_legacy_get_workstreams_returns_410_and_meters(self, client):
         await _create_domain(client)
         topic = await _create_topic(client)
         await _create_workplan(client, topic["id"])
@@ -80,7 +80,8 @@ class TestWorkplanAliasesAndLegacyMeter:
                 "X-StateHub-Component": "old-client",
             },
         )
-        assert r.status_code == 200
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
         assert r.headers["Deprecation"] == "true"
         assert r.headers.get("Sunset")
         assert r.headers["X-StateHub-Replacement"] == "/workplans/"
@@ -91,7 +92,6 @@ class TestWorkplanAliasesAndLegacyMeter:
         assert item["window"]["tenants"] == {"tenant-a": 1}
         assert item["window"]["users"] == {"alice": 1}
         assert item["window"]["components"] == {"old-client": 1}
-        assert item["retirement_candidate"] is False
 
     async def test_weekly_review_accepts_hours_window(self, client):
         r = await client.post("/legacy-meter/interfaces", json={
@@ -164,7 +164,7 @@ class TestWorkplanAliasesAndLegacyMeter:
         assert item["retirement_candidate"] is False
         assert item["retirement_reason"] == "1 call(s) in review window"
 
-    async def test_workplan_finish_does_not_meter_legacy_completion_event(self, client):
+    async def test_legacy_patch_workstream_returns_410_and_meters(self, client):
         await _create_domain(client)
         topic = await _create_topic(client)
         wp = await _create_workplan(client, topic["id"])
@@ -174,15 +174,14 @@ class TestWorkplanAliasesAndLegacyMeter:
             json={"status": "finished"},
             headers={"X-StateHub-Component": "old-client"},
         )
-        assert r.status_code == 200
-        assert r.json()["status"] == "finished"
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
 
         summary = (await client.get("/legacy-meter/summary")).json()
         items = _summary_by_key(summary)
         assert items["rest_api:PATCH /workstreams/{workstream_id}"]["window"]["components"] == {
             "old-client": 1
         }
-        assert items.get("event_subject:org.statehub.workstream.completed") is None
 
     async def test_legacy_workplan_index_returns_410(self, client):
         r = await client.get(
@@ -390,9 +389,100 @@ class TestWorkplanAliasesAndLegacyMeter:
             json={"execution_state": "manual", "launch_mode": "manual"},
             headers={"X-StateHub-Component": "old-executor"},
         )
-        assert r.status_code == 200
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
         assert r.headers["X-StateHub-Replacement"] == "/execution/workplans/{workplan_id}/intent"
 
         summary = (await client.get("/legacy-meter/summary")).json()
         item = _summary_by_key(summary)["rest_api:PATCH /execution/workstreams/{workstream_id}/intent"]
         assert item["window"]["components"] == {"old-executor": 1}
+
+    async def test_legacy_post_workstream_returns_410_and_meters(self, client):
+        await _create_domain(client)
+        topic = await _create_topic(client)
+        repo = await _create_repo(client, slug="legacy-create-repo")
+
+        r = await client.post(
+            "/workstreams/",
+            json={
+                "repo_id": str(repo["id"]),
+                "topic_id": str(topic["id"]),
+                "slug": "legacy-create",
+                "title": "Legacy Create",
+                "status": "active",
+            },
+            headers={"X-StateHub-Component": "old-creator"},
+        )
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
+        assert r.headers["X-StateHub-Replacement"] == "/workplans/"
+
+        summary = (await client.get("/legacy-meter/summary")).json()
+        item = _summary_by_key(summary)["rest_api:POST /workstreams/"]
+        assert item["window"]["calls"] == 1
+        assert item["window"]["components"] == {"old-creator": 1}
+
+    async def test_legacy_get_workstream_detail_returns_410_and_meters(self, client):
+        await _create_domain(client)
+        topic = await _create_topic(client)
+        wp = await _create_workplan(client, topic["id"])
+
+        r = await client.get(
+            f"/workstreams/{wp['id']}",
+            headers={"X-StateHub-Component": "old-reader"},
+        )
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
+        assert r.headers["X-StateHub-Replacement"] == "/workplans/{workplan_id}"
+
+        summary = (await client.get("/legacy-meter/summary")).json()
+        item = _summary_by_key(summary)["rest_api:GET /workstreams/{workstream_id}"]
+        assert item["window"]["calls"] == 1
+        assert item["window"]["components"] == {"old-reader": 1}
+
+    async def test_legacy_workstream_dependency_routes_return_410_and_meter(self, client):
+        await _create_domain(client)
+        topic = await _create_topic(client)
+        first = await _create_workplan(client, topic["id"], slug="dep-first", title="First")
+        second = await _create_workplan(client, topic["id"], slug="dep-second", title="Second")
+
+        dep = await client.post(
+            f"/workplans/{first['id']}/dependencies/",
+            json={"to_workplan_id": second["id"]},
+        )
+        assert dep.status_code == 201, dep.text
+        dep_id = dep.json()["id"]
+
+        r = await client.post(
+            f"/workstreams/{first['id']}/dependencies/",
+            json={"to_workstream_id": second["id"]},
+            headers={"X-StateHub-Component": "old-dep-writer"},
+        )
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
+
+        r = await client.get(
+            f"/workstreams/{first['id']}/dependencies/",
+            headers={"X-StateHub-Component": "old-dep-reader"},
+        )
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
+
+        r = await client.delete(
+            f"/workstreams/{first['id']}/dependencies/{dep_id}",
+            headers={"X-StateHub-Component": "old-dep-archiver"},
+        )
+        assert r.status_code == 410
+        assert "retired" in r.json()["detail"]
+
+        summary = (await client.get("/legacy-meter/summary")).json()
+        items = _summary_by_key(summary)
+        assert items["rest_api:POST /workstreams/{workstream_id}/dependencies/"]["window"]["components"] == {
+            "old-dep-writer": 1
+        }
+        assert items["rest_api:GET /workstreams/{workstream_id}/dependencies/"]["window"]["components"] == {
+            "old-dep-reader": 1
+        }
+        assert items["rest_api:DELETE /workstreams/{workstream_id}/dependencies/{dep_id}"]["window"]["components"] == {
+            "old-dep-archiver": 1
+        }