About-page link failure is terminal-only; should be a toast per the funnel rule

Found during #124: Message::LaunchUrl failure reports only to the terminal. Under the funnel's own consistency rule (owner ruling on #124) every pilot-facing failure surfaces visibly; this one is minor enough for a toast, not the alert. Small; whoever touches the About page next takes it.

Locate `Message::LaunchUrl` in the About-page UI flow and find where it is currently reported to terminal output. Start by reading that handler and nearby message/toast code paths, then switch the failure path for this case to the existing toast surface (keeping it a non-alert severity). Verify by exercising the About-page launch-url failure scenario so the user sees a visible toast and no longer relies on terminal-only reporting.

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