ci-ubicloud.yml (cherry-picked from the ubicloud-ci experiment branch, green
on run 27375556034: 291 wx + 38 kicad tests in 1h52m) now triggers on main
pushes and replaces ci-full-build.yml and ci.yml. The Hetzner flow needed
create/delete-VM jobs, a PAT + hcloud token, and a shared one-slot
concurrency lock; the Ubicloud runner is a plain runs-on label and finished
faster end-to-end. wasm-opt-bench.yml stays (dispatch-only Hetzner bench
harness, unrelated to CI).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>