Add isValidBeadsPrefix() to validate prefix format before passing to exec.Command. Prefixes from config files (detectBeadsPrefixFromConfig) are now validated to contain only alphanumeric and hyphen characters, start with a letter, and be max 20 chars. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>