Remove duplicate overview.md from brand-guides

The README.md already contains the same content (with fixed paths).

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

Author: louis-pre

docs/brand-guides/SUMMARY.md

@@ -1,7 +1,6 @@
 # Brand Guides
 
 * [Brand Guides](README.md)
-* [Overview](overview.md)
 * [2N Intercom Systems](2n-intercom-systems/README.md)
   * [2N System Set Up Instructions](2n-intercom-systems/2n-system-set-up-instructions.md)
   * [Get started with 2N Intercoms](2n-intercom-systems/get-started-with-2n-intercoms.md)