fix(tests): strip the synced durable timestamp in the flushed-message dict comparison

tests/agent/test_compression_rotation_state.py

@@ -1616,7 +1616,7 @@ class TestTodoSnapshotScaffoldingTails:
             {
                 k: v
                 for k, v in m.items()
-                if k not in {"_row_id", _DB_PERSISTED_MARKER}
+                if k not in {"_row_id", "timestamp", _DB_PERSISTED_MARKER}
             }
             for m in compressed
         ] == expected

tests/agent/test_steer_compaction_persistence.py

@@ -40,4 +40,4 @@ def test_flushed_steer_keeps_one_display_identity_across_compactions(tmp_path):
     visible = db.get_messages(session_id, include_compacted=True)
     assert [(row["display_kind"], row["content"]) for row in visible] == [
         ("steer", steer["content"]),
-    ]
+    ]