fix(session): preserve history across storage relocation

Co-authored-by: lmzopq <1646888+lmzopq@users.noreply.github.com>

tests/cli/test_session_restore.py

@@ -0,0 +1,31 @@
+from pathlib import Path
+
+from typer.testing import CliRunner
+
+from nanobot.cli import commands
+from nanobot.config.loader import load_config
+from nanobot.session.manager import SessionManager
+
+
+def test_sessions_restore_workspace_command_prepares_downgrade(
+    tmp_path: Path,
+    monkeypatch,
+) -> None:
+    workspace = tmp_path / "workspace"
+    config_path = tmp_path / "instance" / "config.json"
+    config = load_config(config_path)
+    config.agents.defaults.workspace = str(workspace)
+    manager = SessionManager(workspace, sessions_root=config_path.parent / "sessions")
+    session = manager.get_or_create("cli:rollback")
+    session.add_message("user", "restore-me")
+    manager.save(session, fsync=True)
+    monkeypatch.setattr(commands, "_load_runtime_config", lambda *_args: config)
+
+    result = CliRunner().invoke(commands.app, ["sessions", "restore-workspace"])
+
+    assert result.exit_code == 0, result.output
+    assert "Restored 1 session file(s)" in result.output
+    restored = workspace / "sessions" / manager._get_session_path(session.key).name
+    assert restored.exists()
+    assert "restore-me" in restored.read_text(encoding="utf-8")
+    assert manager._get_session_path(session.key).exists()