[Feat] Add prefetch for Mooncake cross-stage paged KV transfer in HunyuanImage3 (#7637)

Signed-off-by: Acerak01-fy <wfy2003324@163.com>

tests/diffusion/test_diffusion_engine_dummy_run.py

@@ -220,6 +220,7 @@ def test_paged_kv_profile_requests_match_per_rank_batch(
         width=1024,
         guidance_scale=5.0,
         num_image_inputs=3,
+        num_frames=1,
     )
     engine._prepare_request_for_admission.assert_called_once_with(request)