Mobile CI/CD Runner Pool: Build Queue & Cache Simulator (2D)

A top-down 2D companion to the runner-pool CI/CD simulator: commits arrive as a Poisson-ish stream, wait in a FIFO queue until one of a fixed number of runners frees up, then that single runner carries the job through checkout, build, test and sign/deploy lanes drawn as colored segments. Build-cache hit rate shortens only the build stage, test flakiness sends a fraction of jobs back for a retry (up to three attempts before it's marked failed), and the runner-count and arrival-rate sliders push the pool from comfortably under capacity into queue-growth saturation — with queue wait, throughput and runner utilization computed live from the actual simulated job history, the same dynamics fastlane/GitHub Actions/Bitrise fleets show under real commit load.