[Diffusion] Add Worker contracts and RPC plumbing for Scheduler-managed paged KV cache (#5550)

Signed-off-by: Acerak01-fy <wfy2003324@163.com>
Signed-off-by: Hongsheng Liu <liuhongsheng4@huawei.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

tests/diffusion/test_diffusion_model_runner.py

@@ -341,7 +341,7 @@ def test_execute_stepwise_streaming_returns_chunks_at_boundaries(monkeypatch):
     monkeypatch.setattr(model_runner_module.current_omni_platform, "max_memory_allocated", lambda: 0)
     scheduler_output = SimpleNamespace(
         finished_req_ids=set(),
-        scheduled_new_reqs=[SimpleNamespace(request_id="req", req=req)],
+        scheduled_new_reqs=[SimpleNamespace(request_id="req", req=req, diffusion_kv_metadata=None)],
         scheduled_cached_reqs=SimpleNamespace(request_ids=[]),
     )
 
@@ -381,7 +381,7 @@ def test_execute_stepwise_streaming_decodes_final_only_pipeline(monkeypatch):
     monkeypatch.setattr(model_runner_module.current_omni_platform, "max_memory_allocated", lambda: 0)
     scheduler_output = SimpleNamespace(
         finished_req_ids=set(),
-        scheduled_new_reqs=[SimpleNamespace(request_id="req", req=req)],
+        scheduled_new_reqs=[SimpleNamespace(request_id="req", req=req, diffusion_kv_metadata=None)],
         scheduled_cached_reqs=SimpleNamespace(request_ids=[]),
     )
 
@@ -561,7 +561,11 @@ def _make_scheduler_output(num_reqs: int):
     reqs = [_make_request() for _ in range(num_reqs)]
     for i, req in enumerate(reqs):
         req.request_id = f"req-{i}"
-    return SimpleNamespace(scheduled_new_reqs=[SimpleNamespace(req=req) for req in reqs])
+    return SimpleNamespace(
+        scheduled_new_reqs=[
+            SimpleNamespace(request_id=req.request_id, req=req, diffusion_kv_metadata=None) for req in reqs
+        ],
+    )
 
 
 @pytest.mark.core_model