fix: replace Chinese comments in requirements.txt with English to fix pip decode error on Windows

pip on Windows uses GBK codec by default and fails on UTF-8 Chinese
characters in requirements.txt.

api/insurance/requirements.txt

@@ -1,34 +1,31 @@
-# 保单智能客服系统 — 后端依赖
-# 基于 Flask 的独立后端
-
-# Web 框架
+# Web framework
 Flask==3.0.0
 Flask-CORS==4.0.0
 gunicorn==21.2.0
 gevent==23.9.1
 gevent-websocket==0.10.1
 
-# 数据库
+# Database
 SQLAlchemy==2.0.23
 Flask-SQLAlchemy==3.1.1
 psycopg2-binary==2.9.9
 alembic==1.13.0
 
-# 缓存
+# Cache
 redis==5.0.1
 
-# 认证
+# Auth
 PyJWT==2.8.0
 bcrypt==4.1.2
 
-# HTTP 客户端
+# HTTP client
 requests==2.31.0
 httpx==0.25.2
 
-# 工具
+# Utils
 python-dotenv==1.0.0
 pydantic==2.5.0
 pydantic-settings==2.1.0
 
-# 日志
+# Logging
 loguru==0.7.2