Refresh model providers automatically and support Codex subscription UI

[shiqimei]

Adding a provider in the browser left Errand's settings stale unless the user had first clicked its own Add model provider button. Refresh the catalog whenever Settings is open and when the app regains focus, becomes visible, or reconnects. Hidden/offline windows skip background refresh, and closing Settings stops its short polling loop.

Select menus also measure their option labels, icons, and selection indicator instead of inheriting the narrower trigger width, while clamping to the viewport. The full Codex subscription label was verified in the desktop menu.

Also update the guidance and icon for connected Codex subscriptions. Opening provider settings for a new agent no longer creates a redundant error toast over the dialog's close button.

Backend dependency: runta#1314, including read-only subscription discovery for device-login credentials.

Validation:

• Typecheck, lint, all 181 tests, and build passed on GCP. New regressions cover returning from a browser and adding a provider externally while Settings stays open.
• macOS arm64 packaging and native smoke passed.
• Real Errand UI against app.forge / api.forge: device sign-in, the user's newly connected Codex subscription, provider selection, and Atlas creation succeeded. Atlas used the terminal to compute 137 * 29, write/read a file, then recalled ORCHID-0921 and read back 3973 in the follow-up conversation.