Add Windows support for PTY and cross-platform build scripts in desktop application

Improvements

• CorePrevent TimeoutOverflowWarning by capping setTimeout delay to maximum 32-bit signed integer value
• DesktopAdd in-app update toasts to desktop application
• DesktopAdd subagent mention support to desktop application@dbpolito
• TerminalDon't show 'Agent not found' toast for subagents
• DesktopAdd context window configuration to app