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/utils/clipboardUtils.ts

@@ -6,10 +6,12 @@
 
 import * as fs from 'node:fs/promises';
 import * as path from 'node:path';
-import { execCommand } from '@qwen-code/qwen-code-core';
+import { createDebugLogger, execCommand } from '@qwen-code/qwen-code-core';
 
 const MACOS_CLIPBOARD_TIMEOUT_MS = 1500;
 
+const debugLogger = createDebugLogger('CLIPBOARD_UTILS');
+
 /**
  * Checks if the system clipboard contains an image (macOS only for now)
  * @returns true if clipboard contains an image
@@ -115,7 +117,7 @@ export async function saveClipboardImage(
     // No format worked
     return null;
   } catch (error) {
-    console.error('Error saving clipboard image:', error);
+    debugLogger.error('Error saving clipboard image:', error);
     return null;
   }
 }