Complete framework characterization baseline

docs/roadmap/step3.md

@@ -2,8 +2,9 @@
 
 ## Status
 
-Accepted scope. Implementation has not started. The ordered execution plan is
-in [implementation.md](implementation.md).
+Completed on 2026-07-27. The target state below is characterized by the
+passing baseline; its ordered implementation record is in
+[implementation.md](implementation.md).
 
 ## Purpose
 
@@ -38,7 +39,7 @@ injected-client behavior, and reserved provider parameters.
 
 ## Target State
 
-At completion:
+The completed baseline provides:
 
 - tests destined for Promptkit use only Promptkit-destined testdata or
   fixtures generated within the test;
@@ -165,13 +166,13 @@ Step 3 is complete when:
 - the full roadmap behavior list has a clear, non-duplicative test owner;
 - tests that require Step 4 rewrites are explicitly identified;
 - no production behavior or public API changed;
-- all validation in Stage 5 passes; and
+- all required validation passes; and
 - the main migration roadmap records the Step 3 gate as complete.
 
 Migration Step 4 must not begin until these criteria are satisfied.
 
 ## Lifecycle
 
-This is a temporary implementation roadmap. Once Step 3 is complete and its
-gate status is recorded in the main migration roadmap, this file may be removed;
-repository history retains the detailed implementation record.
+This completed implementation roadmap remains the concise characterization
+record for the migration. Repository history retains the detailed implementation
+record.