Expose Markdown validation selection

docs/roadmap/implementation.md

@@ -446,8 +446,8 @@ Undefined references and HTML prose remain governed by parser interpretation.
 
 **Completion:** Complete. The internal checker resolves committed destinations,
 checks supported fragments, preserves inspection errors, and reports distinct
-outside-checkout and submodule observations. Public selection and shared executor
-wiring remain in Stage 11.
+outside-checkout and submodule observations. Stage 11 exposes this checker
+through public and profile selections and the shared executor.
 
 **Outcome:** Committed Markdown navigation is checked with boundary observations.
 
@@ -477,6 +477,14 @@ missing-object, and traversal-cancellation cases.
 
 ## Stage 11: Expose Markdown selection and complete validation integration
 
+**Completion:** Complete. `ValidationSpec.Markdown` and
+`validation.markdown` select the shared committed-link checker through both
+public operations and CLI profile commands. Omitted/null settings disable the
+check; an empty object enables it, and the boundary option maps explicitly.
+Warnings use the shared output writer, while Markdown failures stop product
+checks and builds. GoDoc, profile, consumer, CLI, and internal documentation
+now describe the operational behavior.
+
 **Outcome:** All agreed validation selections work through both public operations.
 
 1. Add `MarkdownValidationSpec`, `ValidationSpec.Markdown`, and their JSON fields.