fix(evidence): reconcile generations safely

harness/tht/search/evidence.py

@@ -56,7 +56,9 @@ def active_evidence_hits(store: CorpusStore, vector_store, embedding, *, limit:
     ]
 
 
-def resolve_evidence_file(store: CorpusStore, evidence_id: str) -> str:
+def resolve_evidence_file(
+    store: CorpusStore, evidence_id: str, *, materialized_root=None,
+) -> str:
     manifest = store.active_manifest()
     if manifest is None:
         return ""
@@ -64,9 +66,8 @@ def resolve_evidence_file(store: CorpusStore, evidence_id: str) -> str:
         frontmatter = document.metadata.get("frontmatter", {})
         identifiers = {document.document_id, document.source_id, str(frontmatter.get("id", ""))}
         if evidence_id in identifiers:
-            # Validate the immutable bytes through the dirfd/O_NOFOLLOW reader before
-            # handing the path to legacy session-artifact consumers.
-            store.read_document(document.document_id)
-            path = store.resolve_document(document.document_id)
+            root = materialized_root or (store.root / "runtime")
+            filename = document.document_id.removeprefix("doc:") + ".md"
+            path = store.materialize_document(document.document_id, root / filename)
             return str(path) if path else ""
     return ""