hardhat --init cleanup

[kanej]

The Hardhat v3 alpha includes --init support. Testing for alpha has shown we need some follow up tasks.

TODO

• Tests for installation of --init, this doesn't need to be e2e but it should test at a minimum it should prove that spawn works on different platforms.
• --init doesn’t show “help us improve…”
• --init doesn’t check for existing dependencies.
  • e.g. if you have viem already installed in the package, it just installs it again, potentially a different version
  • Maybe we should check this before even copying any file and fail
    • except for a hardhat clash, which will be common

[galargh]

One of the items listed in the original description wasn't directly related to --init so I moved it to a separate issue - #5960