feat(auth): discontinue Qwen OAuth free tier (2026-04-15 cutoff) (#3291)

* feat(auth): discontinue Qwen OAuth free tier (2026-04-15 cutoff)

The Qwen OAuth free tier has reached its end-of-life date. This updates
all client-side messaging, blocks new OAuth signups, and guides existing
users to alternative providers.

* fix(test): add getModelsConfig mock and update QWEN_OAUTH test expectations

- Add getModelsConfig() to Config mocks in gemini.test.tsx (3 failures)
- Update validateNonInterActiveAuth test to expect exit for QWEN_OAUTH
  since validateAuthMethod now returns an error for discontinued free tier

packages/cli/src/config/webSearch.ts

@@ -4,7 +4,6 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { AuthType } from '@qwen-code/qwen-code-core';
 import type { WebSearchProviderConfig } from '@qwen-code/qwen-code-core';
 import type { Settings } from './settings.js';
 
@@ -40,10 +39,8 @@ export interface WebSearchConfig {
 export function buildWebSearchConfig(
   argv: WebSearchCliArgs,
   settings: Settings,
-  authType?: string,
+  _authType?: string,
 ): WebSearchConfig | undefined {
-  const isQwenOAuth = authType === AuthType.QWEN_OAUTH;
-
   // Step 1: Collect providers from settings or command line/env
   let providers: WebSearchProviderConfig[] = [];
   let userDefault: string | undefined;
@@ -77,13 +74,9 @@ export function buildWebSearchConfig(
     }
   }
 
-  // Step 2: Ensure dashscope is available for qwen-oauth users
-  if (isQwenOAuth) {
-    const hasDashscope = providers.some((p) => p.type === 'dashscope');
-    if (!hasDashscope) {
-      providers.push({ type: 'dashscope' } as WebSearchProviderConfig);
-    }
-  }
+  // Step 2: DashScope auto-injection for qwen-oauth was removed when the
+  // free tier was discontinued on 2026-04-15.  Users who explicitly configure
+  // a dashscope provider in settings.json still get it (handled in Step 1).
 
   // Step 3: If no providers available, return undefined
   if (providers.length === 0) {