Validate invocation reporting implementation

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Invocation reporting implementation plan
 
-Status: Stages 1–19 complete. Stage 20 is next.
+Status: Stages 1–20 complete.
 
 ## Objective and authority
 
@@ -760,7 +760,7 @@ notes, accepted ADRs, and deferred-work records remain unchanged.
 
 ## Stage 20: Validate the complete end state and finish
 
-Status: pending.
+Status: complete.
 
 1. Format changed Go files with `gofmt`; review the complete diff for unintended
    behavior changes, unselected restrictions, compatibility machinery, public
@@ -800,6 +800,16 @@ Status: pending.
    validation results, any genuine limitations, and worktree status. Do not
    declare a release or remove the roadmap/plan automatically.
 
+Completion: `gofmt` left the changed Go files formatted. The root, ckconfig, and
+ckprompt workspace suites pass; the root workspace-off suite and focused
+reporter race suite pass. Maintained examples pass for core reporting, quiet
+help/version, scoped PromptKit YAML, and aliases. The composed-example failure
+test confirms an offline smoke report remains available alongside an injected
+operational error and terminal context. The ignored `go.work` still includes
+all three modules and was not committed. Final Markdown links and fragments and
+staged and unstaged whitespace checks pass. All selected roadmap behaviors are
+implemented; no release or publication action was performed.
+
 ## Completion criteria
 
 The sprint is complete when the selected public API replaces the old paths;