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/accounts.py

@@ -1,41 +1,20 @@
 """账号管理路由"""
 
-import re
-import csv
 from fastapi import APIRouter, Depends, HTTPException, Query
-from sqlalchemy.orm import Session
+from sqlalchemy import func
+from sqlalchemy.orm import Session, joinedload
 
 from ..database import get_db
 from ..models import User, Account, AuditLog, LoginTask
 from ..schemas import AccountImport, AccountAssign, AccountTag, AccountOut, BatchAssign
 from ..deps import get_current_user, require_permission
 from ..permissions import user_has_permission
-from sqlalchemy import func
-from sqlalchemy.orm import joinedload
+from ..services.account_service import (
+    cookie_account_ids_query, parse_and_build_accounts,
+)
 
 router = APIRouter(prefix="/api/accounts", tags=["账号管理"])
 
-EMAIL_PATTERN = re.compile(r'^[^\s@|]+@[^\s@|]+\.[^\s@|]+$')
-
-
-def _split_account_line(line: str) -> list[str]:
-    if '|' in line:
-        return line.split('|')
-    if '\t' in line:
-        return line.split('\t')
-    if ',' in line:
-        return next(csv.reader([line]))
-    return line.split()
-
-
-def _cookie_account_ids_query(db: Session):
-    """返回有成功登录记录(cookie非空)的账号ID子查询。"""
-    return db.query(LoginTask.account_id).filter(
-        LoginTask.status == 'success',
-        LoginTask.cookie != '',
-        LoginTask.cookie.isnot(None),
-    ).distinct()
-
 
 @router.get("", response_model=list[AccountOut])
 def list_accounts(
@@ -50,7 +29,7 @@ def list_accounts(
 
     # 只展示已成功登录过的账号
     if has_cookie:
-        query = query.filter(Account.id.in_(_cookie_account_ids_query(db)))
+        query = query.filter(Account.id.in_(cookie_account_ids_query(db)))
 
     # 权限控制：客服只能看分配给自己的
     if not user_has_permission(current, "account:view_all"):
@@ -91,39 +70,7 @@ def import_accounts(
     current: User = Depends(require_permission("account:import")),
 ):
     """批量导入账号。格式：用户名|密码|邮箱|邮箱密码|标签(可选)"""
-    from core.douyu.email_verifier import get_email_config_for_account
-
-    accounts = []
-    skipped = 0
-    for line_num, line in enumerate(req.text.strip().split('\n'), 1):
-        line = line.strip()
-        if not line or line.startswith('#'):
-            continue
-        parts = _split_account_line(line)
-        if len(parts) < 4:
-            skipped += 1
-            continue
-
-        username, password, email, email_password = [p.strip() for p in parts[:4]]
-        tag = parts[4].strip() if len(parts) > 4 else ""
-        if not all([username, password, email, email_password]):
-            skipped += 1
-            continue
-        if not EMAIL_PATTERN.match(email):
-            skipped += 1
-            continue
-
-        email_cfg = get_email_config_for_account(email)
-        accounts.append(Account(
-            username=username,
-            password=password,
-            email=email,
-            email_password=email_password,
-            email_imap_server=email_cfg['server'],
-            email_imap_port=email_cfg.get('port', 993),
-            email_imap_ssl=email_cfg.get('ssl', True),
-            tag=tag,
-        ))
+    accounts, skipped = parse_and_build_accounts(req.text)
 
     if accounts:
         db.add_all(accounts)
@@ -187,7 +134,7 @@ def batch_assign_accounts(
             raise HTTPException(status_code=400, detail="只能分配给客服角色")
 
         # 只能分配已成功登录过的账号（有cookie）
-        cookie_ids_query = _cookie_account_ids_query(db).subquery()
+        cookie_ids_query = cookie_account_ids_query(db).subquery()
         invalid_ids = db.query(Account.id).filter(
             Account.id.in_(req.account_ids),
             Account.id.notin_(cookie_ids_query),
@@ -220,7 +167,7 @@ def assignments_summary(
     current: User = Depends(require_permission("account:assign")),
 ):
     """分配概览：每个客服分配了多少账号（仅统计已成功登录的账号）。"""
-    cookie_subq = _cookie_account_ids_query(db).subquery()
+    cookie_subq = cookie_account_ids_query(db).subquery()
     cookie_accounts = db.query(Account).filter(Account.id.in_(cookie_subq)).subquery()
 
     results = (