v0.68.0: Subagent inactivity timer, Usage Limits settings, and streaming stability fixes

New features

- Subagent inactivity timer - Subagents now automatically stop after 3 minutes of inactivity to prevent idle resource usage
- Usage Limits settings - Configure and view Usage Limits directly within sessions and settings (Factory App)

Bug fixes

- VS Code auto-installation - Fixed embedded VS Code auto-installation in the Factory App
- Factory App stability - Fixed daemon restart issues in the Factory App
- Session resume - Fixed reliability issues when resuming previous sessions
- Streaming stability - Fixed a crash that could occur during streaming retries
- BYOK error handling - Improved error messages for payment and authentication errors with custom API keys
- Context management - Improved handling when conversations exceed context limits
- Image handling for text-only models - Images are now properly handled when using text-only models
- GLM-4.7 error handling - Fixed error handling for GLM-4.7 model errors
- MCP tool compatibility - Improved MCP tool schema sanitization for better compatibility across model providers
- Custom model streaming - Fixed streaming issues with custom models
- Reasoning level display - Fixed reasoning level not displaying correctly after using /model in spec mode
- Authentication reliability - Reliability improvements to authentication mechanisms