New feat banner

[amazingphilippe]

Summary | Résumé

Adding a prototype for a new-feature banner that we can anchor to any part of the UI, or insert as a flowing container where needed.

How it works:

• Add the new feature banner anywhere. We don't want it to hide content (for a11y), so it has to position in the document flow.
• If we plan this well, we can add an optional CSS anchor on a specific element. A caret will point to that anchor for some visual interest.

Next steps:

• Review design principles aas a team for when and how to create these banners
• Figure out a lifespan attribute for hiding these banners
• Figure out how a user can opt out or dismiss these.

Test instructions | Instructions pour tester la modification

• Check any email template where file attachments is enabled.

[github-actions]

🧪 Review environment

https://gga2ussysqkwwumchop464ysei0wbifw.lambda-url.ca-central-1.on.aws/