v0.158.0: Plugin toggles, tab slash-command completion, and login and rendering fixes

New features

- Enable and disable plugins - Turn individual plugins on or off with a new toggle

Improvements

- Tab to complete slash commands - Press Tab to complete slash commands
- MCP authentication - Improved handling of MCP authentication responses and desktop redirects
- Account credit checkout - Subscribe to or upgrade your plan using account credit

Bug fixes

- Invalid API key login - The CLI now exits with an error on an invalid FACTORY_API_KEY instead of stalling at login
- Cancel AskUser prompts - Cancelling an AskUser prompt now interrupts the agent instead of letting it continue
- Duplicate tool approvals - Approval-gated tool executions now render only once
- Windows background processes - Fixed cleanup of background processes on exit on Windows
- Document skills location - Document skills are now written to your current working directory
- Dark mode toggles - Dark mode toggles are now visible and loading spinners animate correctly (app)
- Editable composer - The composer stays editable during session blockers (app)