chore(doc): update version mapping for v3.1.2 release

feat: add .prettierignore for markdown files and update README format…

…ting

docs(readme): update mobile and desktop preview images with gifs

fix(task): 为任务模态框函数添加默认参数和空值处理：防止xxl-job 报错:java.lang.NullPointerExce…

…ption: Cannot invoke \"String.trim()\" because the return value of \"com.xxl.job.admin.core.model.XxlJobInfo.getExecutorHandler()\" is null

为handleCreate和handleEdit函数添加默认参数，并确保executorHandler有默认空字符串值

Merge branch 'feature/v1.0.1'