env.local env does not override shell env

[MichaelrMentele]

Description

Following the steps from here: https://sdk.vercel.ai/docs/getting-started/nextjs-app-router

When running the app, my local env does not resolve/clobber the shell env. Basically if I have the env set and exported at the shell level I would have though env.local would be more specific and would have overridden the value set in the shell. I can see it making sense both ways I suppose but wanted to flag it since it confused me for a good 15 m.

Code example

# .env.local
FOO_BAR=baz

Then in shell
export FOO_BAR=bizzy

Additional context

No response