Update notice shown for Homebrew install that is already at latest version

Description

Claude Code displays an update available notice in the status bar suggesting to run brew upgrade claude-code, but the installed version is already the latest available via Homebrew.

Steps to reproduce

1. Install Claude Code via Homebrew
2. Ensure it's up to date (brew upgrade claude-code reports "the latest version is already installed")
3. Launch claude
4. Observe status bar shows an update is available

Expected behavior

No update notice should be shown when the installed version matches the latest available version in the Homebrew cask.

Actual behavior

Status bar displays an update notice suggesting brew upgrade claude-code, even though version 2.1.87 is the latest available and already installed.

Environment

• Claude Code version: 2.1.87 (Homebrew)
• Platform: macOS (Darwin 25.5.0, Apple Silicon)
• Homebrew is up to date (brew update reports "Already up-to-date")