The reviewer asked this run to look closely at it; no test exercised it. Checks the label span's clipped opacity/max-width and the FAB's square shape while the rail is collapsed, then its read label and wider-than-tall shape once the rail's menu button expands it, waiting past the shared spatial-default spring both morph on (plan step 36, navigation group). Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9