Offer help self-hosting OpenBot in a dismissable banner

[davidmckayv]

A slim, dismissable bar at the top of the signed-in app: "Self-host OpenBot for your organization." with a Talk to an engineer link to https://copilotkit.ai/talk-to-an-engineer?ref=openbot_app. The ref marks an in-app visit, separate from the README's openbot_readme.

How it behaves

• Where: the app shell only (_authed/_app), above the page. Not on sign-in, onboarding, admin or settings.
• Dismiss: the X saves selfHostBannerDismissed: true to the person's preferences, so it stays closed on every device. The bar hides at once and comes back if the save fails.
• Off for everybody: OPENBOT_SELF_HOST_BANNER=false (or 0), reported to the browser through /api/capabilities like OPENBOT_GENERATIVE_UI. For a fork running OpenBot for its own organization. The chart has no value for the generated-interface flag either, so this one goes through config.extraEnv.
• Layout: text, link and X are packed from the left. On localhost CopilotKit's dev inspector floats over the top-right corner, and a hit test showed it covering an X pinned there, so the X could not be clicked.
• Link: an anchor styled as a link, not Button with render, because Base UI gives a rendered anchor role="button". It uses the foreground color, because the link variant's primary measured as a mid grey on the dark bar.

Checked

• bun run typecheck, lint, format:check and build pass.
• New tests: the banner renders when enabled, hides when dismissed or switched off, saves on dismiss, and comes back when the save fails; the config flag; the capability; and the preference patch. Each fails with the code reverted.
• bun run test:ci: the same 8 environment-only failures as main locally, none new.
• In Chrome, on a local stack:
  • the bar renders at desktop width and at 390px, in light and dark;
  • the link carries ref=openbot_app, opens in a new tab, rel="noopener noreferrer";
  • X hides it, and it stays hidden after a reload;
  • with OPENBOT_SELF_HOST_BANNER=false and the preference not dismissed, there is no banner.