Add option to hide startup banner in interactive mode

Feature request

Add a CLI flag (e.g. --no-banner) and/or a settings option to hide the ASCII art startup banner in interactive mode:

 ▐▛███▜▌   Claude Code v2.1.84
▝▜█████▛▘  Opus 4.6 (1M context) · Claude Max
  ▘▘ ▝▝    ~/Documents/bhd/monorepo

Motivation

The banner takes up vertical space in the terminal on every launch. For frequent users who already know what version/model they're running, it's visual noise. A way to suppress it would be appreciated — especially for smaller terminal windows or tiling setups where screen real estate matters.

Suggested implementation

Any of these would work:

• --no-banner CLI flag
• A "showBanner": false setting in .claude/settings.json or user settings
• An environment variable like CLAUDE_NO_BANNER=1