feat(douyu): 精英宝典导入支持按多行账户名筛选

对齐 Cookie 自定义 CK 的粘贴导入方式，按账户名精确匹配并保持粘贴顺序。

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_douyu_account_name_filter.py

@@ -0,0 +1,84 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+from web.backend.database import Base
+from web.backend.models import Account, LoginTask, User
+from web.backend.routers.douyu import (
+    _parse_account_names,
+    list_task_account_ids,
+    list_task_accounts,
+)
+
+
+class TestDouyuAccountNameFilter:
+    def setup_method(self):
+        self.engine = create_engine("sqlite://")
+        Base.metadata.create_all(self.engine)
+        self.session = sessionmaker(bind=self.engine)()
+        self.user = User(username="admin", password_hash="hash", role="super_admin")
+        self.session.add(self.user)
+        self.session.commit()
+
+        self.accounts = {}
+        for name in ("account-a", "account-b", "account-c"):
+            account = Account(
+                username=name,
+                password="password",
+                email=f"{name}@example.com",
+                email_password="mail-password",
+            )
+            self.session.add(account)
+            self.session.flush()
+            self.session.add(
+                LoginTask(
+                    batch_id=f"login-{name}",
+                    account_id=account.id,
+                    created_by=self.user.id,
+                    status="success",
+                    cookie="acf_uid=1",
+                )
+            )
+            self.accounts[name] = account
+        self.session.commit()
+
+    def teardown_method(self):
+        self.session.close()
+        Base.metadata.drop_all(self.engine)
+        self.engine.dispose()
+
+    def test_parse_account_names_trims_and_dedupes(self):
+        assert _parse_account_names(
+            "account-c\n\naccount-a\r\naccount-c\n account-b "
+        ) == [
+            "account-c",
+            "account-a",
+            "account-b",
+        ]
+
+    def test_list_task_accounts_follows_paste_order(self):
+        result = list_task_accounts(
+            search="",
+            tag="",
+            ids="",
+            account_names="account-c\naccount-a",
+            page=1,
+            page_size=50,
+            db=self.session,
+            current=self.user,
+        )
+        assert result["total"] == 2
+        assert [item.username for item in result["items"]] == ["account-c", "account-a"]
+
+    def test_list_task_account_ids_follows_paste_order(self):
+        result = list_task_account_ids(
+            search="",
+            tag="",
+            account_names="account-c\nmissing-name\naccount-a",
+            db=self.session,
+            current=self.user,
+        )
+        assert result["account_ids"] == [
+            self.accounts["account-c"].id,
+            self.accounts["account-a"].id,
+        ]
+        assert result["total"] == 2