Add queue bead type for tracking work queues in Gas Town. This includes:
- QueueFields struct with status, concurrency, processing order, and counts
- Parse/Format functions for queue field serialization
- CRUD methods: CreateQueueBead, GetQueueBead, UpdateQueueFields, etc.
- Queue registered in BeadsCustomTypes for bd CLI support
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>