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/conftest.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+import atexit
+import os
+import shutil
+import tempfile
+from pathlib import Path
+
+# ``k1link.web.app`` builds the installed plugin environment at import time.
+# Pytest imports test modules during collection and future tests may lazy-load
+# it during execution or in a spawned child.  Keep every mutable Mission Core
+# store used by that composition inside one process-scoped test root for the
+# entire pytest lifetime.  Restoring the caller environment after collection
+# would reopen the operator's real stores for lazy imports and child processes.
+_ISOLATED_ENVIRONMENT_KEYS = (
+    "MISSIONCORE_DATA_DIR",
+    "MISSIONCORE_EVIDENCE_DIR",
+    "MISSIONCORE_LEGACY_SESSIONS_DIR",
+)
+_ORIGINAL_ENVIRONMENT = {
+    key: os.environ.get(key) for key in _ISOLATED_ENVIRONMENT_KEYS
+}
+_TEST_RUNTIME_ROOT = Path(
+    tempfile.mkdtemp(prefix="mission-core-pytest-runtime-")
+).resolve()
+_TEST_RUNTIME_ROOT.chmod(0o700)
+
+_ISOLATED_ENVIRONMENT = {
+    "MISSIONCORE_DATA_DIR": _TEST_RUNTIME_ROOT / "data",
+    "MISSIONCORE_EVIDENCE_DIR": _TEST_RUNTIME_ROOT / "evidence",
+    "MISSIONCORE_LEGACY_SESSIONS_DIR": _TEST_RUNTIME_ROOT / "legacy-sessions",
+}
+for _key, _path in _ISOLATED_ENVIRONMENT.items():
+    _path.mkdir(mode=0o700, parents=True, exist_ok=True)
+    _path.chmod(0o700)
+    os.environ[_key] = str(_path)
+
+
+def _restore_environment() -> None:
+    for key, original_value in _ORIGINAL_ENVIRONMENT.items():
+        if original_value is None:
+            os.environ.pop(key, None)
+        else:
+            os.environ[key] = original_value
+
+
+@atexit.register
+def _remove_test_runtime() -> None:
+    _restore_environment()
+    shutil.rmtree(_TEST_RUNTIME_ROOT, ignore_errors=True)