fix(huya): 优化账号密码导入交互并将导入类型严格限制为四段格式

- 交互优化：将账号标签选择器移至弹窗顶部，避免下拉列表向下展开时遮挡底部的'确定'/'导入'按钮
- 格式限制：严格限制仅允许'账号----密码----手机号----接码链接'四段格式导入
- 前后端校验：前端逐行校验格式并提示具体错误行号，后端限制 require_four_segments=True 兜底

tests/test_huya_sms_url.py

@@ -76,6 +76,23 @@ def test_import_password_accounts_persists_sms_url():
     assert added_account.tag == "测试接码"
 
 
+def test_import_password_accounts_strictly_four_segments():
+    """测试账号密码导入默认严格限制仅允许四段格式。"""
+    mock_db = MagicMock()
+    mock_db.query().filter().first.return_value = None
+
+    # 两段、三段会被跳过；仅四段有效行会被导入
+    text = (
+        "user1----pass1\n"
+        "user2----pass2----13800138000\n"
+        "user3----pass3----+14504409332----http://194.163.45.144/api/get_sms?key=xxx\n"
+        "user4----pass4----not_a_url\n"
+    )
+    created, skipped = import_huya_password_accounts(mock_db, text, tag="四段测试")
+    assert created == 1
+    assert skipped == 3
+
+
 def test_solver_strategy_with_and_without_sms_url():
     """测试在遇到 sms_auth2 时，有接码链接不抛异常，无接码链接抛出短信异常。"""
     url = "https://aq.huya.com/p/safe_auth/sms_auth2.html?param=xyz&mobile=14504409332"