[P/D]Make kv-transfer env variable take effect & Fix load-balance proxy (#3981)

### What this PR does / why we need it?
Make kv-transfer env variable take effect and Fix load-balance proxy.

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?
By CI.


- vLLM version: v0.11.0
- vLLM main:
83f478bb19

---------

Signed-off-by: liziyu <liziyu16@huawei.com>
Signed-off-by: nwpu-zxr <zhouxuerong2@huawei.com>
Co-authored-by: liziyu <liziyu16@huawei.com>

vllm_ascend/distributed/mooncake_layerwise_connector.py

@@ -3,6 +3,7 @@ import contextlib
 import copy
 import hashlib
 import math
+import os
 import queue
 import struct
 import threading
@@ -31,6 +32,7 @@ from vllm.v1.core.sched.output import SchedulerOutput
 import vllm_ascend.envs as envs_ascend
 from vllm_ascend.ascend_config import get_ascend_config
 from vllm_ascend.distributed.utils import (align_memory,
+                                           get_transfer_timeout_value,
                                            kv_alltoall_and_rearrange)
 from vllm_ascend.utils import vllm_version_is
 
@@ -602,6 +604,8 @@ class MooncakeLayerwiseConnectorWorker:
 
     def __init__(self, vllm_config: VllmConfig, engine_id: str):
         self._get_prefill_decode_size(vllm_config)
+        os.environ["ASCEND_TRANSFER_TIMEOUT"] = str(
+            get_transfer_timeout_value())
         if self._prefill_tp_size < self._decode_tp_size:
             raise ValueError(
                 f"prefill_tp_size: {self._prefill_tp_size} must be greater than"