Add initial support for workspaces into the TUI

Improvements

• CoreSend context-1m-2025-08-07 beta header to GitLab to enable 1M context window@Krule
• CoreAdd Copilot GPT-5.4 xhigh support
• DesktopFix scroll jitter and loop issues in app
• DesktopSession title turn spinner now displays correctly
• DesktopDismiss toast notifications when questions or permissions are resolved@neriousy