[Feature Request] Persist /color choice across sessions via settings.json

Bug Description
Request: persist /color choice per-project (or globally) /color is currently session-only — running /color orange doesn't persist across sessions, and there's no equivalent key in settings.json (I checked the schema). For users who work in multiple repos and want a visual cue to distinguish sessions per project, this means re-typing the command every time Claude Code starts. Ask: Add a settings.json key (e.g. sessionColor: "orange") that's honoured by both ~/.claude/settings.json (user-wide default) and <repo>/.claude/settings.json (per-project default), where project scope wins. Same merge semantics as other settings. Use case: I work across several repos in one terminal multiplexer. Having each repo's Claude session render in a distinct prompt-bar colour is a tiny but real productivity win — it eliminates "wait, which session am I typing in?" mistakes when context-switching. Today I have to remember to set it manually each session, which usually means I forget until I've already sent something to the wrong one. Acceptable alternatives: - A SessionStart hook hook-type or a settings key that runs slash commands at session start. - Auto-persist the most recent /color choice locally (per-cwd) and reapply on subsequent sessions in that cwd. Either of those gives the same outcome.

Environment Info

• Platform: linux
• Terminal: gnome-terminal
• Version: 2.1.128
• Feedback ID: 2c9c7626-413d-4b89-abcc-079342111a20

Errors

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