fix: alias module so we can access process.server in vite node build

[danielroe]

1. adds ~composition-api alias to allow vite plugins to run on module code (for process.server)
2. inlines https://github.com/unjs/defu temporarily (until packaged with .mjs) - this only became an issue after step 1 above

cc: @pi0

with these changes nuxt/vite#127 should be mergeable

[pi0]

@danielroe Can you please upgeade ufo to 4.0.1? A silly typo fixed :}