fix: Playwright API camelCase → snake_case (Python 版)

- getByPlaceholder → get_by_placeholder
- getByRole → get_by_role
- getByText → get_by_text
- getByTestId → get_by_test_id

tests/web/pages/login_page.py

@@ -18,9 +18,9 @@ class LoginPage(BasePage):
     def __init__(self, page: Page):
         super().__init__(page)
         # ── 定位器声明 ──
-        self.username_input = page.getByPlaceholder("请输入用户名")
-        self.password_input = page.getByPlaceholder("请输入密码")
-        self.login_btn = page.getByRole("button", name="登录")
+        self.username_input = page.get_by_placeholder("请输入用户名")
+        self.password_input = page.get_by_placeholder("请输入密码")
+        self.login_btn = page.get_by_role("button", name="登录")
         self.error_tip = page.locator(".ant-form-item-explain-error")
 
     def login(self, phone: str, password: str, expect_success: bool = True) -> None: