v0.133.1: Context window modal, audio cues, sidebar session menu, and stability fixes

New features

- Context window - New /context slash command and modal for inspecting the current session's context usage
- Audio cues - Optional sounds when a session finishes or is awaiting your input (app)
- Sidebar session menu - Right-click sessions in the sidebar for quick actions (app)

Bug fixes

- Final output visibility - The final output now stays visible above the input box
- New session draft cleared - New session drafts now clear after submitting (app)
- Linear Computer setup link - The "set up Computer" call to action in Linear now points to the correct settings page
- Desktop zoom stability - Hardened desktop zoom handling against host zoom errors (app)