OmniAuth strategy for SQRL login

Identity management, the full SQRL command set, CPS handoff, login-page discovery, a Capybara helper, a CLI and a server conformance suite.

Rack middleware serving the SQRL endpoint, status poll and CPS callback, a Sinatra extension with view helpers, the browser-side script and QR code rendering.

SQRL login for Rails: engine, generator, ActiveRecord stores and Rails 8 Authentication support