fix(test): prevent infinite loop in E2E conftest auto_load_env

`while folder != "/"` 比较 Path 与 str 永远为真，没有 .env 时会死循环卡住整个 E2E 启动。改为按 `folder.parent == folder` 判断到达根目录后退出。

Change-Id: Id62a2804abdffda4f399c5cbbb22a4c6ba41c4e6
Co-developed-by: Claude <noreply@anthropic.com>

Author: congxiao-wxx

tests/e2e/conftest.py

@@ -15,12 +15,18 @@
 
 def auto_load_env():
     folder = Path(__file__).parent
-    while folder != "/":
+    # 一直向上查找 .env 文件，直到根目录为止
+    # / Walk up to root looking for a .env file
+    while True:
         dotfile = folder / ".env"
         if dotfile.exists():
             load_dotenv(dotfile)
             print("load .env:", dotfile)
             break
+        if folder.parent == folder:
+            # 已到根目录，未找到 .env，依赖外部环境变量
+            # / Reached the filesystem root with no .env found; rely on env vars
+            break
         folder = folder.parent