diffy is a dead stupid diff tool.

- curl -F red=@1 green=@2 https://diffy works for 99% of people
- also git diff | curl https://diffy
- Limited for public usage: resulting diffs max ~32kb, max 5 diffs per day and 20 diffs per month per IP. Temporary diffs (retention <=1yr, the max) have separate limits; 20 per day and 200 per month. If your diff is deleted for the retention policy, your counter is decreased.
- Storage: object storage, local cache in Bolt + Cloudflare cache.
- Sustainability: unclear for now, likely that this thing will have 100 regular users who are happy with the limits. I'll tell users who want to lift limits to self-host or send me an email and we can arrange something.
- Retention policy: 5 hits in the first month, then minimum 10 hits per year. Can obviously just be crawlers.

// DIFFP: https://cs.opensource.google/go/x/tools/+/master:internal/diffp/diff.go;l=21?q=diff&sq=&ss=go%2Fx%2Ftools