fix(ui): simplify credential aliases and usage filters

Use plain model name and alias inputs for credential aliases, discard unsaved credential settings on close, and replace usage filters with select-only menus.

tests/credentialAdvancedFields.test.tsx

@@ -12,7 +12,7 @@ const renderAdvanced = (name: string, advanced: Record<string, unknown>, provide
 describe('credential settings interaction', () => {
   it('lets a Codex credential edit aliases directly and hides Claude cloaking', () => {
     const html = renderAdvanced('codex-cbb7bd85-user-team.json', {});
-    expect(html).toContain('Add alias');
+    expect(html).toContain('Add model');
     expect(html).toContain('Credential timezone');
     expect(html).toContain('Asia/Shanghai');
     expect(html).not.toContain('Request cloaking');

tests/credentialAliasPicker.test.tsx

@@ -5,16 +5,19 @@ import { I18nProvider } from '../src/i18n';
 
 const html = renderToStaticMarkup(
   <I18nProvider>
-    <CredentialAdvancedFields name="codex-user.json" advanced={{ model_aliases: [{ name: 'gpt-5', alias: '' }] }}
-      models={[{ name: 'gpt-5', displayName: 'GPT 5' }]} onChange={() => {}} />
+    <CredentialAdvancedFields name="codex-user.json" advanced={{ model_aliases: [{ name: 'gpt-5', alias: 'public-gpt' }] }} onChange={() => {}} />
   </I18nProvider>,
 );
 
-describe('credential alias model picker', () => {
-  it('uses the searchable model picker for both model fields', () => {
-    expect(html.match(/role="combobox"/g)).toHaveLength(2);
+describe('credential alias editor', () => {
+  it('uses plain inputs for the upstream model and client alias', () => {
+    expect(html).not.toContain('role="combobox"');
+    expect(html).toContain('aria-label="Model name"');
+    expect(html).toContain('aria-label="Model alias"');
     expect(html).toContain('value="gpt-5"');
-    expect(html).toContain('Search or enter a model');
-    expect(html).not.toContain('<textarea');
+    expect(html).toContain('value="public-gpt"');
+    expect(html).toContain('aria-label="Expand"');
+    expect(html).not.toContain('Display name');
+    expect(html).not.toContain('Search or enter a model');
   });
-});
+});