Fix underlay provenance and resource path handling

docs/roadmap/remediation.md

@@ -6,6 +6,28 @@ contracts in the [roadmap](sources-and-layering.md) and
 [implementation plan](implementation.md). No implementation fixes are included
 in this review.
 
+## Resolution status
+
+All three findings were addressed on 2026-09-29:
+
+- Composition now fills sequence-descendant origins separately from atomic
+  conflict claims, so initial underlay attribution reaches every surviving node.
+- History reconciliation checks contributing origins and recognizes ancestor
+  replacement events without duplicating their descendant contributions.
+- Native contexts use `fs.ValidPath`; host contexts use `filepath.Localize`
+  before the existing canonicalization and containment checks.
+
+`facade_underlay_origins_test.go` covers imported sequence descendants in first
+and later tiers, resolver/result/explanation agreement, and later mapping
+contributors. `TestResourceContextsPreserveLiteralBackslashes` covers native
+and host resource reads and directory listing. The new tests reproduced all
+three failures before the fixes. The findings below retain the original review
+evidence and acceptance requirements.
+
+Post-fix validation passed: `./scripts/check.sh` and
+`GOPROXY=off go test -race ./...`. Existing sequence replacement, provenance,
+history, and resource-containment tests remain passing.
+
 ## 1. Preserve underlay attribution for sequence descendants (P2)
 
 **Owners:** `internal/engine/load_request.go:174`,