feat: add canonical workflow result models

tests/wf_api/test_models.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+import pytest
+from pydantic import ValidationError
+
+from wf_api.models import HealthResult, JsonProjector
+
+
+def test_json_projector_validates_transport_neutral_payloads() -> None:
+    project_health = JsonProjector(HealthResult)
+
+    assert project_health({"status": "ok", "store_root": "store"}) == {
+        "status": "ok",
+        "store_root": "store",
+    }
+
+
+def test_json_projector_rejects_malformed_payloads() -> None:
+    project_health = JsonProjector(HealthResult)
+
+    with pytest.raises(ValidationError):
+        project_health({"status": "ok"})