feat: better bookmarks

[zeucapua]

Is your feature request related to a problem? Please describe.
While browsing in feeds, I would bookmark posts for different reasons. Trying to read bookmarks afterwards is messy with no directions.

Describe the solution you'd like
As a user, I want to sort, search, and filter bookmarks based on my own categories/tags, as well as pin them to the top.

[erlend-sh]

Also consider supporting the Bookmark lexicon:

• https://github.com/lexicon-community/lexicon/tree/main/community/lexicon/bookmarks
• Adoption of 3rd party lexicons bluesky-social/atproto#3338
• Add bookmarks natively to Bluesky bluesky-social/social-app#7383

[ebwinters]

Also consider supporting the Bookmark lexicon:

* https://github.com/lexicon-community/lexicon/tree/main/community/lexicon/bookmarks

* [Adoption of 3rd party lexicons bluesky-social/atproto#3338](https://github.com/bluesky-social/atproto/discussions/3338)

* [Add bookmarks natively to Bluesky bluesky-social/social-app#7383](https://github.com/bluesky-social/social-app/pull/7383)

+1 - it also supports tagging for filters! I worked on the bookmarks lexicon and Bluesky implementation, would be great to talk more about bookmarks design and using the community bookmark lexicon here for portability. Feel free to message me @western-red-cedar.bsky.social