Starter Pack adoption

This is a very popular tool created by Bluesky that the Fediverse and Mastodon are looking to emulate. It helps to get accounts started and organised.
This is Mastodon’s current implementation that’s being worked on https://github.com/mastodon/mastodon/pull/33121
Here’s a Bluesky blogpost explaining starter packs https://bsky.social/about/blog/06-26-2024-starter-packs

No files, tests, or entry points are listed in the issue. Start by locating onboarding/account-management and discovery-related code paths in the repository, especially any API modules for social grouping. Use the linked Mastodon PR and Bluesky post to derive the required starter-pack behavior and data model, then identify or add tests for pack creation/joining and usage flows. Done means a starter-pack feature is implemented consistently and verified by relevant tests for that flow.

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