Merged pull request on matrix-rust-sdk. Description: [...] I have built this by guiding an LLM (Claude Sonnet 4.5 in Zed) through the requirements, successive refactoring steps and necessary changes. I have also reviewed the results at every point and tested them against Element X iOS. I chose to do so here because it's a standalone component and the perfect testing grounds.

Draft pull request on matrix-authentication-service. Description: Fully vibe-coded, but should be reviewable commit-by-commit