Fix horizontal overscroll revealing blank background

Add overscroll-behavior: contain to prevent elastic rubber-banding.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

Author: 3 people

docs/projects/grcengineering-cheat-sheet/index.html

@@ -162,6 +162,8 @@
 .table-container {
   position: relative;
   overflow: auto;
+  -webkit-overflow-scrolling: touch;
+  overscroll-behavior: contain;
   border-radius: 16px;
   box-shadow:
     0 4px 24px var(--shadow),