fix(namespace): noun-record updates preserve legacy inline HNSW adjacency — the placeholder-adjacency write stamped out pre-codec records' stored connections (crash-window unreachability); codec-era records were never at risk (empty field is the blob marker); pin covers the legacy shape

src/transaction/operations/StorageOperations.ts

@@ -77,8 +77,27 @@ export class SaveNounOperation implements Operation {
       ? null
       : await this.storage.getNoun(this.noun.id)
 
-    // Save new noun
-    await this.storage.saveNoun(this.noun)
+    // PRESERVE stored graph state on updates. Callers stage this op with
+    // placeholder adjacency ({connections: empty, level: 0}) because the
+    // vector index owns those values and persists them at flush. Codec-era
+    // records (2.4.0+) carry an empty connections field by design (adjacency
+    // lives in a separate compressed blob — the placeholder is harmless), but
+    // LEGACY pre-codec records store adjacency INLINE: writing the
+    // placeholder over one stamped out its stored connections, leaving a
+    // crash window (until the next flush) where a reload found the node
+    // unreachable. Stale adjacency in that window is tolerable — HNSW
+    // self-corrects at the reindex flush; EMPTY adjacency is silent recall
+    // loss. The read above is already paid for rollback; preservation is free.
+    const toSave: HNSWNoun =
+      previousNoun && this.noun.connections.size === 0
+        ? {
+            ...this.noun,
+            connections: previousNoun.connections || this.noun.connections,
+            level: previousNoun.level ?? this.noun.level
+          }
+        : this.noun
+
+    await this.storage.saveNoun(toSave)
 
     // Return rollback action
     return async () => {