Shift+R to repeat the last action

This is a bit longer-term, once we have a more rigorously defined architecture for "actions" similar to how Blender does it (where they're searchable, and probably where you can specify the parameters that affect the action using that bottom left menu that appears when the action just occurred). That's related to #741 and #384, which are sort of this issue's prerequisites.

未确定任何文件、测试或入口点。首先阅读 issue #741 和 #384 中关于操作架构的前置条件；完成的标准是 Shift+R 能够在严格定义的操作系统内重复上一次操作。

由索引模型根据 Issue 内容生成。