Feature request: Allow customization of update reminder notification

Feature Request

The "Claude update available" reminder shown at the bottom of the Claude Code screen is hardcoded and not user-configurable.

Desired Behavior

Allow users to customize the update reminder display — for example, to show a compact emoji (e.g. ⬆️) instead of the full text banner. This would be especially useful for users who are already on a frequent update cadence and find the full banner distracting.

Suggested Implementation

A setting in settings.json such as:
"updateNotification": "compact" or "updateNotification": "emoji"

Or integration with the existing statusLine configuration so users can control how update availability is surfaced.