New ~50-line orchestrator that fires Setup.DefaultScript through the
already-shipped PhysicsScriptRunner on entity spawn and stops scripts +
live emitters on despawn. Resolver delegate avoids DatCollection coupling
so the class is fully unit-testable with stubs.
Three xUnit tests cover the three branches: fire-with-script,
no-op-without-script, stop-on-remove. No wiring into the live spawn path
yet -- that lands in the next commit.
Spec: docs/superpowers/specs/2026-05-12-phase-c1.5a-portals-design.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>