Add a bundler/build tool selection

This should probably have:

- Typescript
- tsgo
- tsdown
- zshy
- rolldown
- esbuild

We don't need to bother with older bundlers for now at least, and can focus on "next gen".

By defining these, we should also then know the _build output path_.

By knowing the output path, we can later generate things like:

- `.gitignore`

Look at the existing code to understand how build tools are currently defined and how the output path is determined. The issue mentions adding support for Typescript, tsgo, tsdown, zshy, rolldown, and esbuild. Start by examining the project structure to see where tool configurations are stored. Determine how to define these new tools and their output paths, then test that the .gitignore generation works correctly with the new additions.

索引モデルが issue の本文から書いたものです。