add discovered repos to Stellar and some sub-ecosystems

[ElliotFriend]

Hi, Electric Capital Friends!

I've got a batch of new repos to add to the Stellar ecosystem, as well as some of our sub-ecosystems. I used a script to run a github code search for repos that pull in Stellar SDKs as a dependency. I also did a "vibe check" that each repo represents an actual Stellar project, and not a false positive search result. (I did use Claude Code for some of that task, in case that matters.)

Some of these repos are "multichain" repos that already exist in the taxonomy, attributed to other ecosystems (e.g., https://github.com/OpenZeppelin/openzeppelin-ui). I think the correct syntax for those additions to the Stellar ecosystem is still repadd Stellar <repo_url>? If I'm mistaken about that, I'm more than happy to make a correction.

If there is anything else you need on this PR, I'm more than happy to make adjustments. Thanks!!

Extra Info

• The script I used to run the search can be found here: ElliotFriend/ec-crawler-stellar
• The dictionary of SDKs I was searching for, and the corresponding ecosystem which those SDKs get attributed to, can be found here: ElliotFriend/ec-crawler-stellar/blob/main/crawler/constants.py#L29