fix(wechat-browser): fix upload progress check crashing on second iteration

Runtime.evaluate reuses the same JS execution context across calls in a
session. The previous expression used `const thumbs = ...` which throws
"Identifier 'thumbs' has already been declared" on the second loop
iteration, causing result.value to be undefined and JSON.parse to throw
"JSON Parse error: Unexpected identifier 'undefined'".

Fix by inlining the querySelector into a single expression with no
variable declaration, eliminating the re-declaration error.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

skills/baoyu-post-to-wechat/scripts/wechat-browser.ts

@@ -570,10 +570,7 @@ export async function postToWeChat(options: WeChatBrowserOptions): Promise<void>
     for (let i = 0; i < 30; i++) {
       await sleep(2000);
       const uploadCheck = await cdp.send<{ result: { value: string } }>('Runtime.evaluate', {
-        expression: `
-          const thumbs = document.querySelectorAll('.weui-desktop-upload__thumb, .pic_item, [class*=upload_thumb]');
-          JSON.stringify({ uploaded: thumbs.length });
-        `,
+        expression: `JSON.stringify({ uploaded: document.querySelectorAll('.weui-desktop-upload__thumb, .pic_item, [class*=upload_thumb]').length })`,
         returnByValue: true,
       }, { sessionId });
       const status = JSON.parse(uploadCheck.result.value);