docs: update CLAUDE.md with auto-merge guidance

Add note to only enable auto-merge on PRs when explicitly requested.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: p-m-p

CLAUDE.md

@@ -84,3 +84,4 @@ The library provides multiple slide transition effects (carousel, fade, cube, ti
 - Always use pnpm when running any node packages
 - Tests enhanced with comprehensive property coverage
 - Don't add comments in code
+- Only set PRs to auto merge when explicitly told to do so