feat: add Visual selection and clipboard editing

src/ruby_host.rb

@@ -28,6 +28,7 @@ module Vamp
       normal newline backspace submit
       search search_next search_previous
       word_next word_previous word_end big_word_next big_word_previous big_word_end
+      select copy cut paste_before paste_after
     ].each do |name|
       action = Action.new("core.#{name}".freeze).freeze
       define_singleton_method(name) { action }
@@ -35,7 +36,7 @@ module Vamp
   end
 
   module Modes
-    %w[normal insert command search].each do |name|
+    %w[normal insert command search visual].each do |name|
       mode = Mode.new(name.freeze).freeze
       define_singleton_method(name) { mode }
     end