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）

web/backend/services/login_service.py

@@ -3,6 +3,7 @@
 import asyncio
 import threading
 import uuid
+from types import SimpleNamespace
 from concurrent.futures import ThreadPoolExecutor, as_completed
 from datetime import datetime, timezone
 from typing import Optional
@@ -10,7 +11,6 @@ from typing import Optional
 from sqlalchemy.orm import Session
 
 from core.douyu import DouyuLogin
-from core.models import Account, ProxyConfig as DouyuProxyConfig
 from core.douyu.proxy import resolve_working_proxy, get_proxy_manager
 from ..models import Account as AccountModel, LoginTask, ProxyConfig as ProxyConfigModel
 
@@ -128,7 +128,7 @@ class LoginBatchRunner:
                 return
 
             try:
-                account = Account(
+                account = SimpleNamespace(
                     username=acc_info["username"],
                     password=acc_info["password"],
                     email=acc_info["email"],
@@ -261,5 +261,34 @@ class LoginBatchRunner:
             self.db.close()
 
 
+class BatchRegistry:
+    """管理运行中的登录批次状态。"""
+
+    def __init__(self):
+        self._batches: dict[str, dict] = {}
+        self._lock = threading.Lock()
+
+    def register(self, batch_id: str, log_queue: asyncio.Queue,
+                 loop: asyncio.AbstractEventLoop, runner: LoginBatchRunner):
+        with self._lock:
+            self._batches[batch_id] = {
+                "log_queue": log_queue,
+                "loop": loop,
+                "runner": runner,
+            }
+
+    def get(self, batch_id: str):
+        with self._lock:
+            return self._batches.get(batch_id)
+
+    def pop(self, batch_id: str):
+        with self._lock:
+            return self._batches.pop(batch_id, None)
+
+
+# 模块级单例
+batch_registry = BatchRegistry()
+
+
 # 在模块末尾导入 SessionLocal（避免循环导入）
 from ..database import SessionLocal