fix(admin): preserve selector contrast while open

AI-Co-Authored-By: Codex

admin-web/src/global.less

@@ -751,6 +751,14 @@ a:focus-visible,
   backdrop-filter: blur(12px);
 }
 
+.bot-selector .ant-select-selection-item {
+  color: #1f3447 !important;
+}
+
+.bot-selector .ant-select-arrow {
+  color: #405469;
+}
+
 .account-button {
   color: #33465a;
 }

admin-web/tests/e2e/admin.spec.ts

@@ -525,6 +525,8 @@ test('深色导航不污染下拉、状态标签与业务弹层的浅色可读
 
   await page.locator('.bot-selector .ant-select-selector').click();
   await expect(page.locator('.ant-select-dropdown')).toBeVisible();
+  await expect(page.locator('.bot-selector .ant-select-selection-item')).toHaveCSS('color', 'rgb(31, 52, 71)');
+  await expect(page.locator('.bot-selector .ant-select-arrow')).toHaveCSS('color', 'rgb(64, 84, 105)');
   await expect(page.locator('.ant-select-dropdown')).toHaveCSS('background-color', 'rgb(255, 255, 255)');
   await expectReadablePair(
     page,