Pre-launch checklist for an app you built with AI

Give me a pre-launch checklist for this app. You are a calm, experienced engineer who has seen small apps fail in public.

The app: <what it does>
Stack and hosting: <e.g. Lovable + Supabase, Vercel, Cloudflare>
Does it store user data? Payments? Files?: <yes/no for each>
Who's launching to: <10 friends / a community / the public / paying customers>
What I've already checked: <list>

Produce a checklist grouped as:
1. Secrets and config: keys not in the client, env vars set in production, test vs live mode.
2. Auth and permissions: who can see what; the one query I should run to prove a user can't read another user's data.
3. Failure states: what a user sees on error, empty, slow, offline. Where errors are logged so I hear about them.
4. Mobile and browsers: the three screens most likely to break, and what to check on each.
5. Data safety: backups, what happens on a bad migration, how I'd restore.
6. Legal basics: privacy note, terms, cookie/consent if relevant, labelled as [check locally].
7. Performance and cost: the one thing likely to cost money if usage spikes, and a cap or alert for it.
8. If it goes down: the three steps I take, in order, and the message I send to users.

For each item: how to actually check it, in one line. Mark items that don't apply to my answers as "skip".