Feature request: persist /color setting across sessions

Summary

The /color command (e.g. /color orange) only applies to the current session and resets when Claude Code is restarted. There's no way to make it persistent.

Proposal

Add a "sessionColor" key to settings.json (or similar config) so users can set a default session color that persists across sessions. For example:

{
  "sessionColor": "orange"
}

Alternatively, support a --color CLI flag so users can alias it in their shell config.

Current behavior

• /color orange sets the color for the current session only
• No config key exists in settings.json, config.json, or any other file to persist this
• /theme already persists across sessions, so /color not persisting is inconsistent

Why this matters

Users who prefer a specific accent color have to manually run /color every time they start a new session. This is a small friction that a one-line config option would eliminate.