There’s a lot here but I would start much more simply.
There are various discussions around app lexicons for making an app directory.
So my suggestion would be to follow the Lexicon Community process, see who is interested in making a working group, and work towards an app lexicon first release.
The key would ideally be at least one project using this live, and include those builders in defining the lexicon.
The Bluesky Directory folks https://blueskydirectory.com are one set of people who have built a database who might be interested in migrating their data to actually be on protocol.
This might be the thing that gets the bsky team to use the same lexicon to list a showcase of apps https://bsky.social/about (they deprecated their showcase and link out to the directory).
Can an app lexicon be broad enough to cover SDKs like Kuba’s SDK.blue?
Maybe this is too much of a stretch, on the other hand, Bluesky Directory covers starter packs and code and a bunch of things, and building something that is immediately useful for our community would be great.
The new atproto.com site only lists a couple of SDKs and might use it.
As npmx has shown, including having a simple like button for packages, would likely be really useful!