[Router] Add load-aware prefill admission and bounded policy proposals (#37843)

Signed-off-by: Vincent Gao <vincentbo@linux.alibaba.com>
Co-authored-by: Kangyan Zhou <zky314343421@gmail.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Shangming Cai <csmthu@gmail.com>

experimental/sgl-router/tests/e2e/k8s_integration/test_lifecycle.py

@@ -13,10 +13,7 @@ by driving the deployment scale.
 
 from __future__ import annotations
 
-import logging
-
 import httpx
-import pytest
 from conftest import (
     NAMESPACE,
     _cleanup_port_forward,
@@ -24,7 +21,7 @@ from conftest import (
     _poll_until,
     _port_forward_start,
     _wait_for_deployment_ready,
-    logger,
+    _wait_for_replacement_pod_ready,
 )
 
 ROUTER_RESTART_PORT = 8092
@@ -132,7 +129,10 @@ class TestRouterRestart:
                 _cleanup_port_forward("router-restart-pre-kill", pf_holder[0])
                 pf_holder[0] = None
 
-            _wait_for_deployment_ready("sgl-router")
+            if old_pod:
+                _wait_for_replacement_pod_ready(old_pod, "app=sgl-router")
+            else:
+                _wait_for_deployment_ready("sgl-router")
 
             pf_holder[0] = _port_forward_start(
                 NAMESPACE, "sgl-router", ROUTER_RESTART_PORT, 8090