Worker struct: TimerWheel → generic WorkerExtension. TickContext: registries moved behind RuntimeExtension. Phases 2.5/5.5/7 generalized. Ctx API split into core (6 methods) vs extension traits (swactor-std). Authored by Claude, lovingly guided by Zachery Aaron Shores-Chmielewski
Write tests for docker integration, as docker is how we will initially handle distribution on heterogeneous hardware.