Fix a 'Pre-transform error' using aliases with Vite

[skirtles-code]

This fixes a problem reported in #7.

When using @ aliases with shadcn-vue, there's an error trying to run the playground and docs packages:

Pre-transform error: Failed to load url /src/lib/utils

The relevant code is:

import { cn } from '@/lib/utils'

The problem isn't unique to shadcn-vue, the same thing would happen for other uses of @ aliases that don't resolve exactly to a file. For example, any imports that don't include the extension, or that rely on resolving to an index file.

The solution implemented here is to pass the new path through this.resolve(), after the @ has been replaced. This will apply the other resolution rules required to handle those cases.

These changes should allow Vite to resolve the aliases correctly, both during dev and for a production build.

There is a related problem with the type-check command. This is still failing to resolve the aliases correctly in the playground and docs packages.