Extend composed consumer with request validation

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # PromptKit request validation implementation plan
 
-Status: Stages 1–6 complete; implementation is ongoing.
+Status: Stages 1–7 complete; implementation is ongoing.
 
 ## Authority, scope, and baseline
 
@@ -411,6 +411,17 @@ making the intentionally failing example a failed completion check.
 **Complete when:** the maintained consumer demonstrates the accepted feature,
 typed selection, shared state, and application-owned defaults without execution.
 
+**Completed:** 2026-10-12. Composed `WithRequestValidation` with the existing
+engine loader, campaign selector, input/state factories, and invocation cache.
+The typed builder loads the selected campaign through that cache and defaults
+only absent `topic` and `mode` variables, preserving explicit empty values and
+operator bindings. Added offline topic and notes fixtures and extended the
+consumer README with both successful file-backed commands and the intentional
+missing-topic failure. Composed tests passed with
+`GOTOOLCHAIN=local go test -count=1 .`; both successful README commands emitted
+the expected two-field YAML confirmation, and the missing-topic command exited
+with status 1 for the native required-artifact error.
+
 ## Stage 8: Update canonical documentation for implemented behavior
 
 **Primary files:** GoDoc, `docs/cli.md`, `docs/consumers/guide.md`, README,