Document application-owned alias contracts

docs/roadmap/implementation.md

@@ -694,6 +694,15 @@ all newly documented alias commands also ran successfully.
 canonical owner; no future alias APIs are described as existing before their
 implementation is present. Prose checks and relevant examples agree.
 
+**Completed:** GoDoc now distinguishes canonical `Command` declarations from
+root-installed routing rules and documents captured errors, invalid nil/zero
+values, idempotent duplicates, canonical flag scopes, and invocation paths. The
+CLI reference, consumer guide, maintained example READMEs, internal overview,
+architecture policy, and active developer navigation describe the implemented
+contracts and integration wiring. Local Markdown links and fragments resolved;
+`git diff --check -- '*.md' COPYRIGHT` and the cached equivalent passed. The
+deferred-work record and accepted ADR were left unchanged.
+
 ## Stage 16: Record compatibility impact for the next core release
 
 **Work**