fix: address sglang failures on pre-merge/post-merge workflows (#7255)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

components/src/dynamo/sglang/health_check.py

@@ -7,6 +7,8 @@ sglang-specific health check configuration.
 This module defines the default health check payload for sglang backends.
 """
 
+from __future__ import annotations
+
 import logging
 from typing import Optional
 

components/src/dynamo/sglang/tests/test_sglang_unit.py

@@ -9,6 +9,7 @@ from pathlib import Path
 
 import pytest
 import yaml
+from sglang.srt.disaggregation.utils import FAKE_BOOTSTRAP_HOST
 
 from dynamo.sglang.args import parse_args
 from dynamo.sglang.health_check import (
@@ -274,7 +275,7 @@ async def test_disagg_config_rejects_dynamo_keys(tmp_path, mock_sglang_cli, capf
 def test_disagg_health_check_payload_includes_bootstrap_info():
     payload = SglangDisaggHealthCheckPayload().to_dict()
 
-    assert payload["bootstrap_info"]["bootstrap_host"] == "fake_bootstrap_host"
+    assert payload["bootstrap_info"]["bootstrap_host"] == FAKE_BOOTSTRAP_HOST
     assert payload["bootstrap_info"]["bootstrap_port"] == 0
     assert payload["bootstrap_info"]["bootstrap_room"] == 0
     assert payload["token_ids"] == [1]
@@ -284,5 +285,5 @@ def test_prefill_health_check_payload_is_disagg_compatible_alias():
     payload = SglangPrefillHealthCheckPayload().to_dict()
 
     assert "request" not in payload
-    assert payload["bootstrap_info"]["bootstrap_host"] == "fake_bootstrap_host"
+    assert payload["bootstrap_info"]["bootstrap_host"] == FAKE_BOOTSTRAP_HOST
     assert payload["stop_conditions"]["max_tokens"] == 1