Prove a production server-local ready-client seam #110

Parent

Spec: Complete the review-driven Effect API Query 0.1.0 programme

What to build

A supported local-execution construction decision is backed by installed public Effect APIs and request ownership evidence.

Acceptance criteria

• Prove a production-ready no-network ready-client route/adaptation using current supported public APIs; do not rely on test-client constructors as production guarantees.
• Retain declaration typing, errors, residual services, authentication context, and application-owned resources.
• Use public request instrumentation to demonstrate network absence; preserve request isolation and complete Cause behavior.
• If supported public APIs cannot provide the seam safely, record the exact evidence, documented limitation, and supported ready-client fallback.
• Give the dependent SSR slice a bounded construction decision and executable fixture, without introducing a public client factory or performing ungoverned installs.