fix: prevent notification close buttons from submitting forms - #408

Summary

• set type="button" on the built-in notification close control
• add a regression assertion to the existing close-button test

Native buttons default to type="submit". Notifications can be mounted into a custom container inside a form, so clicking the built-in close control could otherwise submit an unrelated form. The action buttons in this repository already use explicit button types; this aligns the close control with that contract.

Verification

• Exact-base regression: 45 passed, 1 failed because the close button had no type
• Fixed focused file: 46/46 passed
• Fixed full suite: 3 files, 52/52 passed
• npm run tsc
• npm run lint — 0 errors, 10 pre-existing warnings
• npm run compile — ESM, CJS, declarations, and Less compilation passed
• focused Prettier check and git diff --check

I found no open issue or PR addressing notification close-button submission, and audited all current open PR changed files before submission.

AI assistance disclosure: Codex was used to audit native-button defaults, check open work for overlap, add the regression, and run verification. The exact-base failure and final one-attribute runtime change were reviewed locally.

Summary by CodeRabbit

• 错误修复
  • 修复通知关闭按钮在表单中可能意外触发表单提交的问题。
  • 关闭按钮现明确标记为普通按钮类型，提升交互稳定性。