fix(mcp): update OAuth client names and improve MCP commands

- Rename MCP OAuth client names from 'Gemini CLI' to 'Qwen Code'
- Update MCP add/remove/list commands with improved error handling
- Add comprehensive tests for OAuth provider
- Fix token storage test assertions
- Clean up unused i18n translation keys
- Update gemini-converter and window title references

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

packages/cli/src/services/BuiltinCommandLoader.ts

@@ -43,7 +43,7 @@ import { setupGithubCommand } from '../ui/commands/setupGithubCommand.js';
 
 /**
  * Loads the core, hard-coded slash commands that are an integral part
- * of the Gemini CLI application.
+ * of the Qwen Code application.
  */
 export class BuiltinCommandLoader implements ICommandLoader {
   constructor(private config: Config | null) {}