feat(core-shared/conformance): assertFeatureConformance helper

Adds boot-time check that every manifest-declared use case is bound
through withSpan (__instrumented) + withCapture (__captured), with
withAudit (__audited) enforced when audits[] is non-empty. Propagates
inner brands through withSpan so the outermost container-resolved
binding carries all brand markers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-shared/src/conformance/index.ts

@@ -9,3 +9,4 @@ export {
   isAudited,
 } from "./brand-runtime";
 export { ConformanceError } from "./conformance-error";
+export { assertFeatureConformance } from "./assert-bindings";