refactor(harness): route workflow persistence through repositories

harness/tests/test_decision_retract_cli.py

@@ -25,6 +25,8 @@ def test_retract_drops_last_substantive_decision(tmp_path, monkeypatch):
 
     # stub config + session loading (the command only needs a session dir)
     import tht.cli.decision_cmd as mod
+    import tht.cli.session_cmd as session_mod
+    from tht.session.models import SessionManifest, SessionSnapshot
 
     class _Cfg:
         class paths:
@@ -32,7 +34,22 @@ def test_retract_drops_last_substantive_decision(tmp_path, monkeypatch):
 
     monkeypatch.setattr(mod, "_load_config_or_exit", lambda _c: _Cfg())
     monkeypatch.setattr(mod, "load_session_or_exit", lambda _cfg, _s: None)
-    monkeypatch.setattr(mod, "session_dir", lambda _cfg, sid: tmp_path / sid)
+    class _Repository:
+        def get(self, session_id):
+            return SessionSnapshot(
+                manifest=SessionManifest(id=session_id, created_at="2026-01-01T00:00:00Z", question="q", database="d", schema="s"),
+                decisions=list_decisions(tmp_path / session_id),
+            )
+
+        def append_decisions(self, session_id, decisions):
+            from tht.decisions import append_decisions
+
+            return append_decisions(tmp_path / session_id, list(decisions))
+
+    repository = _Repository()
+    monkeypatch.setattr(mod, "load_snapshot_or_exit", lambda _cfg, sid: repository.get(sid))
+    monkeypatch.setattr(mod, "session_repository", lambda _cfg: repository)
+    monkeypatch.setattr(session_mod, "load_snapshot_or_exit", lambda _cfg, sid: repository.get(sid))
 
     retract_cmd(session="2026-01-01-000000-x", config=Path("x"))