Attribute reader shutdown failures to checks that read content

docs/roadmap/remediation.md

@@ -1,6 +1,6 @@
 # Performance Implementation Remediation
 
-**Status:** Remediation in progress; R1 complete.
+**Status:** Remediation in progress; R1–R2 complete.
 
 **Review baseline:** df064bd, reviewed on 2026-10-09 against the
 [performance target](performance.md) and
@@ -90,6 +90,12 @@ tracking remains internal implementation bookkeeping.
 later selected check that has no applicable files. Verify the earlier reader
 user receives the cleanup cause and the child exit error remains discoverable.
 
+**Completion:** Complete. Internal blob-read bookkeeping now identifies the last
+check that actually used the reader. The extended close-failure fixture preserves
+Go-format attribution when Markdown has no files, including the child exit code
+and stderr. The regression failed before the fix and passes afterward; validation
+race tests and compiled public API and dependency checks passed.
+
 ## R3: Qualify Output Allocation Measurements By Their Workload
 
 **Priority:** Low.