feat(miniprogram): add local QR temp-file helper via uqrcodejs.

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

miniprogram/utils/makeQrTempFile.js

@@ -28,7 +28,6 @@ export function makeQrTempFile({ text, canvasId, componentInstance, size = 200 }
       const ctx = uni.createCanvasContext(canvasId, componentInstance)
       qr.canvasContext = ctx
       qr.drawCanvas()
-      // drawCanvas 内部会 ctx.draw；稍延迟再导出
       setTimeout(() => {
         uni.canvasToTempFilePath(
           {