Chat-slot agents were being persisted as durable entries in openclaw.json,
causing spurious workspace directories (e.g. chat-slot-main-1) to appear.
Only explicit workspace creation via init now creates durable agent entries.
Workspace discovery and session routing ignore chat-slot internals.
- Removed unused functions related to session index management.
- Added DELETE endpoint to remove a web chat session and its associated file.
- Added PATCH endpoint to update session metadata, including renaming sessions.
- Streamlined file writing for new session creation.
