Solid Queue 1.6.0 adds fiber workers for AI agent job orchestration

Solid Queue 1.6.0 introduces fiber-based workers that replace the thread-per-job model with cooperative multitasking via the Async gem. Hundreds of concurrent jobs can run on a single OS thread, cutting memory overhead and context-switching costs for agent workflows.

• mode: fiber and max_fibers set the number of concurrent fibers per worker process
• Fiber stacks are kilobytes versus 1–2 MB per thread, reducing memory pressure
• Database queries are fiber-aware: a fiber yields when no connection is available
• Blocking I/O in a gem stalls the whole thread, so dependencies need auditing