fix(miniapp): inline createUuid in config to fix DevTools require

WeChat DevTools failed to resolve utils/uuid.js at runtime; move UUID
generation into config.js which is already loaded by app.js.

Co-authored-by: Cursor <cursoragent@cursor.com>

miniapp/utils/messages.js

@@ -1,4 +1,4 @@
-const { createUuid } = require('./uuid');
+const { createUuid } = require('./config');
 const { buildMessageView } = require('./message-display');
 
 function createUserMessage(text) {