Add shared report format flag

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Shared reporting and PromptKit v0.20.0 implementation plan
 
-Status: implementation in progress; Stages 1–3 complete.
+Status: implementation in progress; Stages 1–4 complete.
 
 ## Scope, authority, and execution
 
@@ -160,6 +160,11 @@ boundary in GoDoc.
 
 ## Stage 4: Universal format input, core version, and a core consumer
 
+**Complete.** Core format selection, version reporting, and a maintained core
+consumer use the shared report path. Focused parser, routing, completion, and
+reporting tests and the root workspace suite (`GOTOOLCHAIN=local go test ./...`
+with Go 1.27.0) passed. Integration migrations remain in later stages.
+
 Extend neutral core flag metadata and parser selection in
 [metadata.go](../../internal/commandmeta/metadata.go),
 [parser.go](../../parser.go), and the internal Cobra adapter. Add core-owned