Add SUMMARY.md and README.md for Brand Guides section

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

Author: louis-pre

docs/brand-guides/README.md

@@ -0,0 +1,9 @@
+---
+description: >-
+  Brand-specific integration guides for connecting and configuring devices and
+  access control systems through Seam.
+---
+
+# Brand Guides
+
+This section contains manufacturer-specific guides for integrating devices and access control systems with Seam. Each guide covers setup instructions, configuration details, and brand-specific considerations.