Desktop: Plan/Build buttons not visible until switching tabs

Bug report

In OpenCode Desktop, the agent mode Plan/Build buttons are not visible until you switch tabs. After switching to another tab and back, the buttons appear.

Environment

• OpenCode Desktop version: 1.18.11
• OS: Linux (CachyOS), Wayland
• Install: AppImage (Electron)

Steps to reproduce

1. Start OpenCode Desktop in a fresh session (or after a restart).
2. Look at the composer/input area — the Plan and Build buttons are not shown.
3. Switch to another tab and back (or open a new tab).
4. The Plan/Build buttons now appear and stay visible.

Expected behavior

The Plan/Build buttons should be visible immediately when the app starts, without needing to switch tabs.

Actual behavior

The buttons only render after a tab switch forces a re-render. This happens every time the app is restarted (the state is not persisted).

Notes

• The buttons exist in the settings (general.showCustomAgents = true in the desktop app's default.dat); they just do not paint until a tab change triggers a redraw.
• Possibly related to the newLayoutDesigns / layoutTransitionEligible settings observed in the desktop app config.