Homebrew update suggestion should check latest Homebrew formula version and clarify npm-only releases

Problem

When Claude Code is installed via Homebrew and detects it's out of date, it suggests running brew upgrade claude-code. However, the Homebrew formula often lags behind the latest npm release. This creates a confusing experience: users run brew upgrade as suggested, but still see the out-of-date warning because Homebrew simply doesn't have the latest version yet.

Suggested improvement

The CLI already detects the Homebrew install context. It should also fetch the latest available Homebrew formula version and use a three-way comparison:

• Current version (installed)
• Latest Homebrew formula version
• Latest npm version

Then show a targeted message:

If Homebrew has the latest npm version:

A new version of Claude Code is available. Run brew upgrade claude-code to update to X.X.X.

(current behavior — no change needed)

If Homebrew lags behind npm:

A new version of Claude Code is available. The latest version on Homebrew is X.X.X (brew upgrade claude-code), but the most recent release (X.X.X) is only available via npm: npm install -g @anthropic-ai/claude-code

Why this matters

• Users who just ran brew upgrade are confused when they still see an update warning — they did what was asked.
• The current message implies brew upgrade will fully resolve the issue, which is often not true.
• With this change, Homebrew users get an honest, actionable message and are clearly guided to npm if they want the latest release — without being forced to switch.

🤖 Filed via Claude Code