wip(k1): checkpoint connection recovery rewrite

Capture the current unreleased K1 connection, recovery, lifecycle, viewer, and test work as a single known-bad baseline for subsequent fixes.

tests/test_session_store.py

@@ -173,6 +173,8 @@ def test_evidence_root_is_private_and_configurable(
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
     repository = tmp_path / "repo"
+    monkeypatch.delenv("MISSIONCORE_EVIDENCE_DIR", raising=False)
+    monkeypatch.delenv("MISSIONCORE_DATA_DIR", raising=False)
     assert (
         resolve_missioncore_evidence_dir(repository)
         == (repository / ".runtime" / "mission-core" / "evidence" / "sessions").resolve()