v0.1.2

• docs(readme): move the "See it work — a 30-second live demo" section above the fold — the demo section (animated SVG + one-command reproduction) now sits right after the badges and before the Table of Contents in all 11 language READMEs, instead of after the Why section where it took two screens of scrolling to reach; structure moved verbatim, checker constants unchanged (still 45 headings / 7 tables / 21 code blocks / 18 TOC anchors) —— README demo 段上移到首屏："看它干活——30 秒真机演示"段（动画 SVG + 一条命令复现）从 Why 段之后移到徽章之下、目录之上，11 语言同步；此前要滚两三屏才能看到，现在打开首页即见；结构原样平移，校验器常量不变（仍为 45 标题 / 7 表格 / 21 代码块 / 18 TOC 锚点）。