fix: attach only safe user fields to req.user

[ethnic17]

What

Updated the auth middleware to only fetch safe user fields using Prisma select. Also simplified the /me route to return req.user directly because it contains safe fields.

Fixes #17

Type of change

• Bug fix
• New feature
• Breaking change
• Documentation update

Proof of work

Tested /api/v1/auth/me locally and verified that the response now only contains the safe selected user fields:
id, email, name, picture, phone, thumbsUp, thumbsDown

Checklist

• I claimed this issue before starting work
• Branch name follows the convention (feature/, fix/, docs/)
• Commits follow Conventional Commits format
• CI is passing (lint, prettier, build)
• I have self-reviewed my own code
• Any non-obvious decisions are explained with a comment in the code