Improve error handling when .env file is not present

[azrikahar]

Need to verify this for all existing examples except SvelteKit (which was implemented in #70).

[freekrai]

@azrikahar I have a few ideas about this, will vary based on stack of course but zod is useful for checking env vars

[azrikahar]

Sounds great! Zod definitely would be more robust here 👍

[freekrai]

Yeah zod or envalid, where envalid is specifically for env vars, so will pick one.

The fresh example currently uses envalid but once I choose one I'll update them all to be the same.

[rijkvanzanten]

Linear: ENG-100