feat(cli): migrate console calls to debugLogger and stdioHelpers (M3 Phase 7-9)

Route CLI console.* calls to structured logging:
- Debug/internal diagnostics → debugLogger (logfile)
- User-facing output → writeStdoutLine/writeStderrLine/clearScreen (stdioHelpers)
- Add stdioHelpers.ts with writeStdoutLine, writeStderrLine, clearScreen
- Migrate pre-session files (gemini.tsx, sandbox.ts, config.ts) to stdioHelpers
- Migrate extension/MCP commands to stdioHelpers
- Migrate non-interactive session/control to debugLogger
- Migrate UI hooks and components to debugLogger

packages/cli/src/ui/components/QwenOAuthProgress.tsx

@@ -12,6 +12,7 @@ import Link from 'ink-link';
 import qrcode from 'qrcode-terminal';
 import { Colors } from '../colors.js';
 import type { DeviceAuthorizationData } from '@qwen-code/qwen-code-core';
+import { createDebugLogger } from '@qwen-code/qwen-code-core';
 import { useKeypress } from '../hooks/useKeypress.js';
 import { t } from '../../i18n/index.js';
 
@@ -29,6 +30,8 @@ interface QwenOAuthProgressProps {
   authMessage?: string | null;
 }
 
+const debugLogger = createDebugLogger('QWEN_OAUTH_PROGRESS');
+
 /**
  * Static QR Code Display Component
  * Renders the QR code and URL once and doesn't re-render unless the URL changes
@@ -161,7 +164,7 @@ export function QwenOAuthProgress({
           },
         );
       } catch (error) {
-        console.error('Failed to generate QR code:', error);
+        debugLogger.error('Failed to generate QR code:', error);
         setQrCodeData(null);
       }
     };