feat: migrate from Foundation to Fomantic-UI

Swap foundation-rails for fomantic-ui-sass across the gem's own
layout/menu/alerts partials and all 11 generic scaffold resources
(pages, news, faqs, quotes, images, directories, keywords, yml_files,
contact_forms, newsletter_subscriptions, users). Foundation grid/button
classes replaced with Fomantic ui.form/ui.button/ui.table conventions;
legacy Foundation mixins in the custom component sass (panel, button,
grid-row/grid-column) rewritten as plain CSS since they no longer exist
once foundation_and_overrides.scss is gone.

Also fixes a real bug found along the way: boolean_text used
`.present?` on values, but SimplyCouch stores booleans as the strings
"0"/"1" — and "0".present? is true in Ruby, so it always rendered
"Yes" regardless of actual value. Now uses ActiveModel::Type::Boolean.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/assets/javascripts/cmtool/application.js.coffee

@@ -1,6 +1,6 @@
 #= require jquery
 #= require jquery_ujs
-#= require foundation
+#= require semantic-ui
 #= require ace/ace
 #= require moment
 #= require ace/theme-monokai
@@ -19,7 +19,9 @@
 #= require_self
 
 $ ->
-  $(document).foundation()
+  $('.ui.dropdown').dropdown()
+  $('.ui.checkbox').checkbox()
+  $('.message .close.icon').on 'click', -> $(@).closest('.message').transition('fade')
   collapsible.setup()
   html_edit.setup()
   yml_edit.setup()
@@ -38,7 +40,7 @@ $ ->
       layout: $('#page_layout').val()
     $.post url, page: params, (response)->
       iframe.attr 'src', url
-      $('#preview-modal').foundation('reveal', 'open')
+      $('#preview-modal').modal('show')
     false
 
   $("[data-time]").each ->