False positive 'Update available' in statusline on Homebrew install (v2.1.92)

Description

The statusline shows a false positive update notification even though the installed version is already the latest according to Homebrew.

Environment

• Version: 2.1.92
• Install method: Homebrew cask (claude-code)
• OS: macOS Darwin 25.4.0
• Auto-update channel: stable

Steps to Reproduce

1. Install Claude Code via brew install claude-code
2. Observe the statusline — it shows:

``
currentVersion: 2.1.92
Update available! Run: brew upgrade claude-code
``

1. Run brew upgrade claude-code
2. Output: Warning: Not upgrading claude-code, the latest version is already installed

Expected Behavior

No update notification shown when already on the latest version.

Actual Behavior

Statusline renders the update notice even though Homebrew confirms 2.1.92 is already the latest.

Notes

• autoUpdatesChannel is set to stable in ~/.claude/settings.json
• minimumVersion is also set to 2.1.92
• Notification persists across restarts