Ruby gets an ERB editor mode (HTML with embedded Ruby), Ruby / Rake / RSpec run configuration types, and a Settings › Languages & Frameworks › Ruby page for choosing the interpreter (Auto picks the `.ruby-version` / mise / asdf install, else `ruby` on PATH).
- Run: `.rb` scripts run from the editor context menu, `_spec.rb` / `_test.rb` files narrow an RSpec or Rake (`SPEC=` / `TEST=`) configuration, and Rakefile tasks are detected; Rake and RSpec go through `bundle exec` when the project has a Gemfile. The chosen interpreter's `ruby`, `bundle`, `rake` and `rspec` are used and its bin directory is put on PATH.
- Configuration forms rebuild from a raw command line keeping option values with their options (`--format documentation`, `-I lib`), and a new Ruby configuration opens in the Ruby form with the script still to fill in.
- External Libraries lists the Ruby standard library and the bundle's gems, including those Bundler installs inside the project (`vendor/bundle`).
- Ruby is part of the frontend settings defaults and normalization, so the selected interpreter survives a settings round-trip.
Closes#719
Co-authored-by: retsef <2175889+retsef@users.noreply.github.com>