fix: remove unused import in session sort test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Hooman Mehr

tests/test_session_cli.py

@@ -313,7 +313,7 @@ def test_sessions_sorted_most_recent_first(self, tmp_path):
         import json
         import time
 
-        from baft.sessions import _SESSION_DIR, get_active_sessions
+        from baft.sessions import get_active_sessions
 
         # Create temp session dir
         session_dir = tmp_path / "sessions"