Bootstrap Fly.io Env Sync Script

Create a script that reads a .env file and converts it into batched fly secrets set commands.

What Gets Created

1. scripts/env-to-fly-secrets.sh — The sync script (from template)
2. .env.prod — Created from .env.sample if it exists and .env.prod doesn't (user fills in real values)
3. .gitignore update — Ensures .env.prod is ignored
4. Justfile recipe (optional) — If a justfile exists, adds a fly-secrets recipe

Features of the Script