Feat: Wait List?

At startups we've worked at/for in the past, they implement a **`Wait List` `before`** the `App` is fully built
so that marketing efforts can commence in parallel to development.

# Examples

There's no shortage of examples on Dribbble: https://dribbble.com/tags/waitlist
https://dribbble.com/shots/20470789-AlignUI-Design-System-Waitlist-Page

https://user-images.githubusercontent.com/194400/218269855-f15e4d5d-b2c9-45c6-b6d2-df6544a051da.mp4




# Context

As an `Engineer` I've always thought that all efforts should be focussed on the `product`, 🧑‍💻
and that _artificial_ wait lists are a bit of an **anti-pattern**. 👎
***Why*** make people _wait_ if the `product` is `ready` for them to **`try` it _now_**? 🤷‍♂️

> "_Waiting lists have been associated with negative psychological and physiological responses such as anxiety and stress; more uncertain, unexpected and longer waits lead to further aggravation of these symptoms_" ~ [https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0265542](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0265542#:~:text=Waiting%20lists%20have%20been%20associated,symptoms%20%5B18%2C%2019%5D.)

I still maintain that forcing people to _wait_ to use a `product` is lame as it destroys momentum.
The _only_ case I would consider it would be if we didn't already have an `MVP`
***or*** we thought our `MVP` was too poorly executed and we had an _unmissable_ marketing opportunity
and could afford to worry about post-event/opportunity "conversion rate" ...

# Possibly _Valid_ Use/Situations

Imagine that you as the founder/product-owner of the `App` want to _review_ each signup
and send a _personal_ message welcoming the person to the `App`.
Feel free to correct me, but I don't think we want to _personalise_ the `App` onboarding experience. 💭

The only other reason for rate-limiting and waitlisting people is a _technical_ bottleneck.
And this one is real: `GMail` only allows `250` outbound emails to be sent per day. 📧
Once we reach that limit, we either need more `Google Accounts` or a rate-limit.

If we had **`250`** sign-ups per day we'd have **_very_ good problems**!

No files, tests, or entry points are identified. First clarify whether a wait-list feature is wanted, including the signup review, onboarding, and Gmail rate-limit cases described here. Done should be a confirmed scope with an agreed user flow and acceptance criteria.

Written by the indexing model from the issue text.