Base directory for overlay filesystem. Path: ~/.cache/ollmchat/{overlay-datetime}/ Example: /home/alan/.cache/ollmchat/overlay-20250115- 143022/
Callers can build derived paths using GLib.Path.build_filename(): - Upper directory: GLib.Path.build_filename(overlay_dir, "upper") - Work directory: GLib.Path.build_filename(overlay_dir, "work") - Mount point: GLib.Path.build_filename(overlay_dir, "merged")