[Feature]: 建议增加格式工具栏

[StrollStars]

Pre-flight checks

• I have searched existing issues and discussions for a similar request.
• This request is about Markra itself, not a provider-specific support question.

Problem

目前编辑格式只能通过格式菜单调用（手打除外），操作没有通过工具栏来得快捷。

Proposed solution

看到有issue中提到，目前有AI快捷输入框，增加格式工具栏会增加UI复杂度，因此可以考虑放置在编辑区顶部。
当然更好的方案是提供选项，浮动工具栏可以是格式工具栏或者是AI快捷输入框。

Product area

Editing

Alternatives considered

No response

Additional context

No response