Pin GitHub Action dependencies to commit SHAs for security

Pin oven-sh/setup-bun and anthropics/claude-code-base-action to specific commit SHAs instead of version tags to ensure reproducible builds and improve supply chain security.

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

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

.gitignore

@@ -1,4 +1,3 @@
-.DS_Store
 node_modules
 
 **/.claude/settings.local.json