[Feature]: Avoid modifying existing codes/configs when init modernjs from an existing repo

[yf-yang]

What problem does this feature solve?

I am trying to convert a module repo to modern.js module, so I run pnpm create @modern-js, it is the recommended way to init an existing repo. Actually it does the following:

1. Update package.json (overrides everything)
2. Update src/index.ts
3. Commit working changes

Change 1 is unpleasing as existing repo has its own dependencies, scripts...
Change 2/3 are unexpected. Editors could have caches and those changes are not even explicitly notified, so I spent hours figuring out if rspack etc. have bugs.

Suggestion:

1. When enabling modern.js in an existing repo, do incremental change instead of complete overwrite.
2. Notify the file changes, git commits, and anything else that I haven't even observed.

What does the proposed API look like?

Nope