Preserve validation cancellation during reader shutdown

docs/internal/validation.md

@@ -54,7 +54,8 @@ neighboring files. Each tree owns one lazy Git blob reader; direct tree users
 must close it when finished. The shared validation executor closes its tree on
 every return before product checks or build callbacks run. A metadata-only
 selection never starts the reader. Per-read contexts cancel an in-flight blob
-exchange without tying the reader lifetime to a short-lived caller context.
+exchange. The context supplied when creating the tree governs the reader
+lifetime, including shutdown and child reaping.
 Regular-file reads return independent caller-owned byte slices and are not
 retained by the tree. Symlink targets are retained as immutable owned strings
 by blob object ID; explicitly reading a symlink still returns independent

docs/roadmap/remediation.md

@@ -1,6 +1,6 @@
 # Performance Implementation Remediation
 
-**Status:** Required follow-up; remediation pending.
+**Status:** Remediation in progress; R1 complete.
 
 **Review baseline:** df064bd, reviewed on 2026-10-09 against the
 [performance target](performance.md) and
@@ -59,6 +59,12 @@ shutdown is still blocked, and verify completion, child cleanup, and preserved
 cancellation identity. Retain coverage of read cancellation, successful closure,
 and preservation of an earlier check failure.
 
+**Completion:** Complete. The tree retains its operation context for the reader
+lifetime. An EOF-synchronized regression now verifies shutdown cancellation,
+cancellation identity, and child reaping; it failed before the fix and passes
+afterward. Race tests passed for validation, Git, and process packages, including
+existing read cancellation, successful closure, and primary-failure coverage.
+
 ## R2: Attribute Shutdown Failures To A Check That Read Content
 
 **Priority:** Medium.