feat(button): 增加 circle 配置项 (#733)

[wanchun]

修复内容

FButton 加 circle 配置项 —— 圆形 icon-only 按钮，与 primary/default/warning/danger 等 type 兼容。

改动

• button.tsx —— 加 circle: Boolean prop (default false)，classList 拼接 fes-btn-circle
• style/index.less —— 加 .fes-btn-circle { border-radius: 50%; padding: 0; }
• button-733.spec.ts —— 4 个行为测试

验证

PATH="$HOME/.nvm/versions/node/v22.22.3/bin:$PATH" ./node_modules/.bin/vitest run components/button

5/5 tests passed (1 老 + 4 新)。

改动文件

3 files / 55+ / 2-

Closes #733

[wanchun]

Closed as part of v3 rebuild from chore/test-infra. Original v1/v2 PRs being superseded by clean re-implementation (vitest + playwright + docs).