fix(core): re-point source records when a per-user move merges entries

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/core/src/entries.ts

@@ -579,6 +579,16 @@ async function moveEntry(
     await moveEngagements(k, userId, src.id, dst.id, actor);
     await writeEntry(k, src, {}, actor, { extra: { deleted_at: nowIso() } });
   }
+  if (result.id !== src.id) {
+    // The moved entry merged into another one: source records that mapped to it keep syncing into the
+    // survivor. Engagements keep their ids when re-parented, so their mappings stay valid.
+    await k
+      .updateTable("source_records")
+      .set({ target_id: result.id })
+      .where("target_entity", "=", "entry")
+      .where("target_id", "=", src.id)
+      .execute();
+  }
   if (opts.undo) return result;
 
   await repointCopiesAndListItems(k, userId, src.workId, target.id, actor);