docs: fix the request-detail handbook clip — start with the sidebar open

The clip began recording before the request sidebar had opened, so its first
second showed the Approvals list's status-chip column cropped to where the
sidebar would appear — fragments floating on white, which read as broken.
Re-recorded starting with the sidebar already open: it now shows the full
request detail (stepper, balance, reason, decision) and switches to the
Coverage tab. Also smaller (504 KB).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: Frank Karlitschek