Typed ITraceSink/TraceEvent seam in Age.Engine (zero deps, allocation-free
hot path); relocate CallScript/OnStub off IHost; Null + Text sinks; CLI
--trace; Godot dispatch hack retired onto a sink. Serilog/EventSource
deferred to optional edge sinks.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
