DevBuilder’s output path should respect the root property of ViteConfig

[haruleekim]

I noticed some issues while using this plugin.

1. DevBuilder's ourDir is not consistent.

   Looking at the code written, I think you intended to refer to the same location as outDir in ViteConfig.
   But it doesn't work if $(cwd) is not the same as the root of ViteConfig.
   So I modified outDir's path resolution logic to refer to the root of ViteConfig.

2. DevBuilder always tries to copy the $(cwd)/public directory.

   This path must also be determined by referring to the root of ViteConfig, not $(cwd).
   And the publicDir property of ViteConfig, not const literal "public".
   So I modified them to do so.

Thank you so much for creating this good plugin.