fix: Remove 111 cross-section redirects from .gitbook.yaml

These redirects had sources in the Guides section but targets in
API Reference or Brand Guides. Space-level redirects can't cross
sections — they were silently 404ing. Imported as site-level
redirects via the GitBook UI instead.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: louis-pre