Consolidate selected overlay acquisition

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Consolidation Implementation Plan
 
-Status: in progress. Stages 1 through 8 are complete; follow Stage 9 through Stage 20 in order.
+Status: in progress. Stages 1 through 9 are complete; follow Stage 10 through Stage 20 in order.
 The target executor is a Luna coding agent working through one end-to-end sprint.
 
 ## Authority, Baseline, And Execution
@@ -413,7 +413,7 @@ sources. Migrated the ordinary backfill and reordered-source context test. The
 selected-overlay adapters remain for Stage 9. Focused context/acquisition tests,
 `GOTOOLCHAIN=local GOPROXY=off go test ./...`, and `git diff --check` passed.
 
-## Stage 9 — Migrate Selected Overlays Without Merging Their Semantics
+## Stage 9 — Migrate Selected Overlays Without Merging Their Semantics (Complete)
 
 **Owners:** engine `selected_overlay.go`, ordinary `applyInputLayers`, and
 `assembleLayeredInput`.
@@ -445,6 +445,14 @@ ordinary and independent layered overlay semantics remain distinct. Run A when
 buildable; carry any genuine remaining migration dependencies to the next
 integration opportunity instead of adding scaffolding or stopping the sprint.
 
+Progress notes (2026-10-25): introduced the named overlay request and migrated
+ordinary and independent layered overlay acquisition to resolved facts plus
+explicit access. Replaced the variadic compatibility branch with the existing
+collection-aware path, removed old context adapters, and retained overlay
+validation timing, source evidence, budgets, version protection, and close
+reporting. Validation group A, consumer examples, the full Go suite, and
+`git diff --check` passed.
+
 ## Stage 10 — Give Import Responsibilities Focused Files
 
 **Owners:** engine `imports.go` and new `import_acquisition.go`,