brew upgrade claude-code hint shown in status line even when already on latest version

Description

The status line always shows brew upgrade claude-code even though the installed version is already the latest.

Steps to Reproduce

1. Install claude-code via Homebrew
2. Launch Claude Code
3. Notice brew upgrade claude-code displayed in the status line on the right

Expected Behavior

The update hint should not appear when the installed version is already up to date.

Actual Behavior

Running brew upgrade claude-code returns "already up-to-date", but the hint continues to appear every session.

Environment

• Claude Code version: 2.1.86
• Homebrew formula version: 2.1.86
• OS: macOS Darwin 25.4.0 (Apple Silicon)
• Installed via: Homebrew Cask (/opt/homebrew/Caskroom/claude-code/2.1.86)