Verify smoke-test integration boundaries

docs/roadmap/implementation.md

@@ -678,6 +678,15 @@ Scope: a small number of consequential integration regressions.
 Validate: focused race-enabled tests for these assembled paths. Keep cases small
 and each risk owned once; do not introduce a second end-to-end state-matrix suite.
 
+**Completed: 2026-10-13.** Added public-boundary regressions for shared Run and
+SmokeTest admission, cancellation/failure permit recovery, retained HTTP and
+decoded-usage evidence, application-resource and observer isolation, disclosure,
+and cross-backend default routing with an endpoint override. Existing focused
+generation/use-case tests continue to cover deterministic interrupted backoff
+and undispatched reacquisition aggregation. Validation passed:
+`go test -race . ./internal/usecase ./internal/generation ./internal/engine`,
+`go vet ./...`, and `git diff --check`.
+
 ## Stage 18: Complete Canonical Documentation
 
 Scope: GoDoc and existing consumer, format, integration, and internal owners.