refactor: 补全services层+消除core/models.py冗余+修复network.py缩进错误

高优先级问题1 - Router层业务逻辑泄漏:
- 新建 services/proxy_service.py: 从routers/proxy.py提取ProxyService类，
  封装代理/白名单测试逻辑、全局状态管理、所有core/ import
- 新建 services/account_service.py: 从routers/accounts.py提取
  split_account_line、cookie_account_ids_query、parse_and_build_accounts，
  封装core.douyu.email_verifier的import
- 重写routers/proxy.py为薄HTTP/WS层，移除所有core/直接依赖
- 精简routers/accounts.py，从account_service导入业务函数
- 将_active_batches全局状态移入login_service.py的BatchRegistry类
- routers/login.py改为使用batch_registry单例

高优先级问题2 - 两套models.py冗余:
- 删除core/models.py（Account dataclass + ProxyConfig死代码）
- 在core/douyu/login.py新增AccountLike Protocol替代Account dataclass
- login_service.py中Account(...)构造改为SimpleNamespace(...)
- 清理core/__init__.py导出

附带修复:
- core/geetest/common/network.py的get_picture()函数缩进错误
  （缺少if match:块和data赋值语句）

core/douyu/login.py

@@ -4,11 +4,10 @@ import re
 import json
 import time
 import requests
-from typing import Mapping, Optional, Tuple
+from typing import Mapping, Optional, Protocol, Tuple
 from urllib.parse import urlsplit, urlunsplit
 from loguru import logger
 
-from core.models import Account
 from .crypto import encrypt_password, encrypt_nickname_or_phone
 from .email_verifier import EmailVerifier
 from .proxy import ProxyManager, get_proxy_manager
@@ -25,6 +24,17 @@ from core.geetest.common.network import (
 from utils.http_logger import log_http
 
 
+class AccountLike(Protocol):
+    """DouyuLogin 所需的最小账号接口，ORM 对象或 SimpleNamespace 均可满足。"""
+    username: str
+    password: str
+    email: str
+    email_password: str
+    email_imap_server: str
+    email_imap_port: int
+    email_imap_ssl: bool
+
+
 class LoginResult:
     """登录结果"""
 
@@ -57,7 +67,7 @@ class DouyuLogin:
 
     def __init__(
         self,
-        account: Account,
+        account: AccountLike,
         proxy: Optional[str | Mapping[str, str]] = None,
         proxy_api_url: Optional[str] = None,
         timeout: tuple[float, float] = REQUEST_TIMEOUT,