AurumBanner

Aurum's banner primitive — a persistent, top-anchored, full-bleed tonal status strip. The SwiftUI port of aurum-android's AurumBanner. It is the persistent counterpart of the transient AurumToast: same tonal palette and status glyphs, but structural (square corners, full-bleed, a bottom hairline) rather than a floating rounded pill, and it stays until the caller dismisses it.

Each tone pairs a feedback.* subtle background with the matching intense content colour and a per-tone leading status glyph. An opaque bgPageBase base is painted under the tint so the strip reads solid over any backdrop. Optionally renders a single inline text action (e.g. "Retry") and, when onDismiss is non-nil, a trailing close ✕.

When the banner touches the top screen edge its backgrounds bleed under the status bar automatically (SwiftUI background extends into safe areas) while the content stays clear — the equivalent of Android's windowInsets parameter, with no parameter needed.

This is a presentational primitive — it does not own the show/hide lifecycle. Pair it with caller-owned state (or AurumBannerHost).

Use for persistent, top-anchored, app- or page-level status the user must stay aware of — offline / no-connection, scheduled downtime, degraded service, account warnings (KYC pending, payment failed). The persistent counterpart to the transient AurumToast: pick the tone from semantic intent. For ephemeral confirmations use AurumToast; for modal / destructive flows use AurumBottomSheet.