Exercise 2: What dotenv/config Does — Possible Solution
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With the `import "dotenv/config";` line removed, running

  $ npx prisma migrate dev

fails with an error saying that no database URL was provided (the
exact wording depends on the Prisma version).

Why:

The config file reads the URL from process.env["DATABASE_URL"]. That
variable is written in the .env file, but a .env file is just a text
file: nothing reads it automatically. The `dotenv/config` import is
what loads the file's contents into process.env. Prisma 7 no longer
loads .env for you, so without the import, DATABASE_URL is undefined
and Prisma has no idea which database to use.

(If DATABASE_URL happens to be set in your shell's environment,
for example with `export DATABASE_URL=...`, it would still work —
which is exactly how many production systems provide it.)

Put the import back before continuing.

WHY THIS WORKS AS AN ANSWER
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It explains the chain — .env file, dotenv, process.env, Prisma — and
notes the Prisma 7 change that makes the import necessary.