sparkengine-ecs-lifecycle-threading-and-memory

Implement Spark::ECS::ISystem with Update and GetName, then register it in EngineSetup.h::CreatePhaseSystemManager in the correct phase. That is the only production registration site. Add a harden test driving InitializeEcsPhaseSystemsImpl to prove the system actually ticks.

Common causes are registering outside CreatePhaseSystemManager, using the unwired CreateGameSystems factory, or the fault isolator auto-disabling a repeatedly throwing system. Check SPARK_GUARDED_UPDATE fault logs and grep EngineSetup.h for your system's registration.

No, the EnTT registry and World wrapper are main-thread only. Gather snapshots on the main thread, process them on JobSystem workers, then write results back on the main thread, following the ParallelPerception pattern.

Physics stepping is module-driven; exactly one owner per process calls Update(deltaTime) or StepFixed, never both. The PhysicsUpdateSystem ECS phase only syncs bodies and transforms and never advances the simulation.

Never destroy entities or mutate components you are iterating inside the view loop. Use Spark::DeferredQueue to mark entities during iteration and Flush after the loop; DeferredQueue itself is not thread-safe.

Route module DLL injection, ABI, and hot-reload questions to the modules skill, CMake and CI questions to the build skill, incident history to failure-archaeology, and live crash diagnosis to the debugging playbook.