Record prompt catalog example completion

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Implementation Plan: Import Discovery and Dependency-Ready Ordering
 
-Status: Stages 1–17 complete; 2 implementation stages remain.
+Status: Stages 1–18 complete; 1 implementation stage remains.
 
 ## Authority, baseline, and execution
 
@@ -650,6 +650,15 @@ reconstruction pass. All fixtures remain local, deterministic, and secret-free.
 Acceptance: consumer tests and executable public examples pass; the consumer
 guide links complete copyable examples rather than duplicating them.
 
+Completion: implemented in commit `de3666a` (`Expand prompt catalog discovery
+example`). Verified with the full consumer suite, executable public examples,
+`./scripts/check.sh`, local documentation links, formatting, and
+`git diff --check`. The maintained catalog now demonstrates load-wide multiple
+patterns, a declaration exception, exclusions, empty optional-search evidence,
+helper-provided IDs, scheduled sequence positions, resource-origin lookup, and
+whole-sequence precedence. A simple required-file example remains available.
+Stage 19 remains.
+
 ## Stage 19 — Finalize documentation and validate the completed unit
 
 Align README orientation, `docs/config.md`, public declaration comments,