feat(create-a-container): admin-configurable announcement banner

[runleveldev]

Summary

Adds a deployment-specific announcement banner shown to all users at the top of the app. The message is stored in the existing admin-editable Settings table, so each environment controls its own banner at runtime — no hardcoded URLs in the repo, no env vars, no restart.

Motivating use case: linking users to a companion app whose URL varies per environment, e.g. Try [Ozwell Studio](https://ozwell-studio-launcher.os.mieweb.org).

How it works

Settings (admin sidebar) → Announcement banner → save. The banner renders immediately for all users; clearing the field hides it.

• New banner_message key in the settings whitelist (PUT/GET /api/v1/settings, stored trimmed)
• Exposed to everyone via the unauthenticated GET /api/v1/health as banner, mirroring the existing isDev/oidcEnabled flow into useServerInfo(); wrapped in try/catch so a DB hiccup never fails the health check
• New AppBanner component mounted in AppLayout between the header and main content
• Supports [text](url) link syntax, parsed client-side into <a> elements (http/https only, no HTML injection) so admin-provided content stays XSS-safe
• Saving settings invalidates the useServerInfo cache so admins see the change without a reload
• Admin docs updated (mie-opensource-landing/docs/admins/settings.md)

Testing

• New integration suite routers/api/v1/__tests__/banner.api.test.js: default-null banner, admin write + unauthenticated exposure via health, non-admin 403, clearing hides it
• Full server suite passes: 4 suites / 28 tests (24 pre-existing + 4 new)
• Client tsc -b clean; production build succeeds

Notes

• useServerInfo caches with staleTime: Infinity, so already-active users pick up banner changes on their next page load
• The banner currently renders only in the authenticated app shell; it's a one-line addition to AuthLayout if we also want it on the login page

[Copilot]

Pull request overview

Adds an admin-configurable announcement banner to the create-a-container SPA, stored per-deployment in the existing Settings table and exposed to clients via the unauthenticated /api/v1/health server-info endpoint.

Changes:

• Add banner_message to admin settings GET/PUT, trimming on write.
• Extend /api/v1/health to include banner and add client-side useServerInfo() consumption + cache invalidation on settings save.
• Add a new AppBanner UI component (with [text](url) link parsing) mounted in AppLayout, plus integration tests and admin docs.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
mie-opensource-landing/docs/admins/settings.md	Documents the new Announcement Banner setting for admins.
create-a-container/routers/api/v1/settings.js	Adds banner_message to the admin settings API payload and persists it trimmed.
create-a-container/routers/api/v1/index.js	Exposes banner via unauthenticated /health so the SPA can render it.
create-a-container/routers/api/v1/tests/banner.api.test.js	Integration coverage for default banner state, admin write, non-admin denial, and health exposure.
create-a-container/client/src/pages/settings/SettingsPage.tsx	Adds banner field to the settings form and invalidates cached server-info on save.
create-a-container/client/src/lib/types.ts	Extends AppSettings with bannerMessage.
create-a-container/client/src/lib/auth.ts	Extends ServerInfo with banner and exports serverInfoKey used for invalidation.
create-a-container/client/src/app/Banner.tsx	New banner component + link parser for [text](url) syntax.
create-a-container/client/src/app/AppLayout.tsx	Mounts the banner between the header and main content.