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/routers/login.py

@@ -11,14 +11,10 @@ from ..models import User, Account, LoginTask, ProxyConfig as ProxyConfigModel
 from ..schemas import LoginBatchRequest, LoginTaskOut
 from ..deps import get_current_user, require_permission, authenticate_websocket
 from ..permissions import user_has_permission, get_user_permissions
-from ..services.login_service import LoginBatchRunner
+from ..services.login_service import LoginBatchRunner, batch_registry
 
 router = APIRouter(prefix="/api/login", tags=["登录任务"])
 
-# 运行中的批次: batch_id -> {log_queue, loop, runner}
-_active_batches: dict[str, dict] = {}
-_active_batches_lock = threading.Lock()
-
 
 @router.post("/batch")
 async def create_batch(
@@ -68,13 +64,8 @@ async def create_batch(
 
     batch_id = runner.batch_id
 
-    # 先注册到全局，再启动线程，确保 WebSocket 连接时能找到
-    with _active_batches_lock:
-        _active_batches[batch_id] = {
-            "log_queue": log_queue,
-            "loop": loop,
-            "runner": runner,
-        }
+    # 先注册到批次注册表，再启动线程，确保 WebSocket 连接时能找到
+    batch_registry.register(batch_id, log_queue, loop, runner)
 
     # 启动线程
     thread = threading.Thread(target=runner.run, daemon=True)
@@ -155,8 +146,7 @@ def stop_batch(
     batch_id: str,
     current: User = Depends(require_permission("login:batch")),
 ):
-    with _active_batches_lock:
-        batch = _active_batches.get(batch_id)
+    batch = batch_registry.get(batch_id)
     if batch:
         batch["runner"].stop()
         return {"message": "已发送停止信号", "success": True}
@@ -175,8 +165,7 @@ async def ws_login_logs(websocket: WebSocket, batch_id: str):
     await websocket.accept()
 
     # 从已注册的批次中获取 log_queue（由 create_batch 创建）
-    with _active_batches_lock:
-        batch = _active_batches.get(batch_id)
+    batch = batch_registry.get(batch_id)
     if not batch:
         await websocket.send_json({"level": "error", "message": "批次不存在或已结束"})
         await websocket.close()
@@ -198,5 +187,4 @@ async def ws_login_logs(websocket: WebSocket, batch_id: str):
     except WebSocketDisconnect:
         pass
     finally:
-        with _active_batches_lock:
-            _active_batches.pop(batch_id, None)
+        batch_registry.pop(batch_id)