Bump httpx2 from 2.10.0 to 2.12.0 - #3481

This push did not change the pull request's own code (it only updated the base branch underneath it, rewrote the branch's history, or added an empty commit): its changes are the same, line for line, as at the commit that was already reviewed, and that review left no blocking issue open (optional notes from it may remain), so it stands and a new review was not started. To review this commit now, comment @claude review on the pull request, or click Re-run on this check.