perf(session): reuse immutable event snapshots

packages/compaction/compaction-basic/tests/compaction-basic.spec.ts

@@ -882,7 +882,7 @@ describe('compaction region transaction', () => {
     expect(head.content[0]?.type === 'text' ? head.content[0].text : '').toContain('<compacted-summary>')
     expect(head.content.at(-1)).toEqual({ type: 'text', text: '</compacted-summary>' })
 
-    const replay = Session.create(SessionId('replay'), [...session.snapshotEvents()])
+    const replay = Session.create(SessionId('replay'), session.snapshotEvents())
     expect(replay.deriveMessages()).toEqual(session.deriveMessages())
   })