Allow usage of vite aliases in @source

[4ndv]

A continuation of #15159 and #15173

It would be useful to have ability to use vite aliases in @source, some usecases:

1. Using something like @/ui/**/* instead of relative paths
2. Setting absolute path aliases for stuff outside of project, like rubygems (my specific usecase):

import { defineConfig } from 'vite'
import { execSync } from 'child_process'
import tailwindcss from '@tailwindcss/vite'
import RubyPlugin from 'vite-plugin-ruby'

const myGemPath = execSync('bundle show my_gem', { encoding: 'utf8' }).trim()

export default defineConfig({
  plugins: [
    tailwindcss(),
    RubyPlugin(),
  ],
  resolve: {
    alias: {
      '@/my_gem': myGemPath,
    },
  },
})

@source "@/my_gem/**/*";