Document PromptKit request validation

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # PromptKit request validation implementation plan
 
-Status: Stages 1–7 complete; implementation is ongoing.
+Status: Stages 1–8 complete; implementation is ongoing.
 
 ## Authority, scope, and baseline
 
@@ -462,6 +462,15 @@ mandates.
 capability under its assigned owners, with no stale five-callback or
 metadata-only claims covering request validation.
 
+**Completed:** 2026-10-12. Updated ckprompt GoDoc, the CLI reference, consumer
+guidance, README module summary, development orientation and examples, and the
+internal component inventory. The docs distinguish `FromEngine`'s five
+callbacks from explicit validation composition, describe native preparation and
+the minimal success YAML, and scope discovery-only statements to discovery.
+`GOTOOLCHAIN=local go test -count=1 ./...` passed from `integrations/ckprompt`;
+the Stage 7 consumer tests and commands remain unchanged and passed. Changed
+Markdown links and anchors and Markdown whitespace checks passed.
+
 ## Stage 9: Validate the complete end state and finish
 
 1. Format changed Go files and inspect the final diff for scope, generated junk,