/color default no longer resolves to a color, resets to terminal default instead

Version: 2.1.246

What happened
Running /color default used to apply a specific color to the session (cyan) rather than clearing the color entirely. After a recent update, /color default now means no color override at all, so the session tab/prompt bar just falls back to the terminal's own default colors.

Steps to reproduce

1. Run /color (assigns a random color, e.g. pink)
2. Run /color default
3. The tab/prompt bar loses its color entirely instead of returning to the previous default hue

Expected behavior
/color default resets the session to whatever color previously counted as "default" (cyan), or at minimum this change in meaning should be documented in the changelog.

Actual behavior
/color default now means "no color override," a silent semantic change with no changelog entry found.

Impact
Anyone who relied on the previous default color across many sessions (for visually distinguishing tabs when running several Claude Code sessions at once) now has to manually run /color cyan (or their preferred color) in every existing session, and in every new session going forward, since there is no persisted or bulk setting for this.

Related issues

• #44002 (auto-name and auto-color new sessions)
• #37349 (dynamic session context label with color coding)

Neither of the above covers this specific regression: the meaning of "default" itself changing without documentation.