Plan step 32. The Phase C rewrite checked the stored collapse at 1600px
with a new visit(), but every visit opens a fresh browser context with
empty storage, where the rail rightly starts expanded. The test now
resizes the page that holds the choice.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9