[Feature Request] Expose welcome banner title color as customizable theme token

Bug Description
The welcome message color is customizable via theme tokens, but the "Claude Code" title at the top of the boot box appears hard-coded to salmon/red. After theming my welcome message green, the title now visibly mismatches.

Can you expose this color as a theme token (e.g. welcomeBannerTitle) so the boot screen can match custom themes end-to-end?

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.142