- Create OriginManagerDialog with list of configured origins
- Show connection status for remote origins
- Allow setting default origin
- Add/Edit/Remove buttons (Add/Edit show placeholder for now)
- Wire up 'Manage Origins...' button in OriginSelectorWidget
- Prevent removal of built-in local origin
Part of Issue #15: Multi-instance Silo configuration UI
- Create OriginSelectorWidget class (QToolButton with dropdown menu)
- Add OriginSelectorAction to create widget in toolbars
- Add Std_Origin command registered in CommandStd.cpp
- Add widget to File toolbar (before New/Open/Save)
- Connect to OriginManager fastsignals for origin changes
- Add Catppuccin Mocha styling for the widget
- Widget shows current origin name/icon with connection status overlay
This implements Issue #13: Origin selector toolbar widget
