feat: add page_settings JSON property + ACE JSON mode

- Add property :page_settings (Hash, default {}) to Page model
- JSON.parse string input in setter (form submits as text)
- Add collapsible 'Page Settings (JSON)' section to page form
- Support data-mode='json' attribute for ACE editor
  (html_edit.js.coffee: check textarea data-mode attribute)

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

@@ -17,6 +17,10 @@ class HtmlEdit
         editor.setValue template_field.val(), -1
         editor.getSession().setMode 'ace/mode/slim'
         console.log "Editing Emblem using Slim mode for ACE editor"
+      else if data_mode = text_field.data('mode')
+        editor.setValue text_field.val(), -1
+        editor.getSession().setMode "ace/mode/#{data_mode}"
+        console.log "Editing #{data_mode} using ACE editor"
       else
         editor.setValue text_field.val(), -1
         editor.getSession().setMode 'ace/mode/handlebars'

app/views/cmtool/pages/_form.html.slim

@@ -37,6 +37,12 @@ javascript:
     .field
       = f.label :footer
       = f.text_area :footer, rows: 15, cols: 80, class: 'html-content'
+  = collapsible_content 'Page Settings (JSON)' do
+    .field
+      = f.label :page_settings
+      %p.help-text JSON configuration for this page. Use Ace editor in JSON mode.
+      = f.text_area :page_settings, rows: 12, cols: 80, class: 'html-content', 'data-mode' => 'json',
+        value: (f.object.page_settings.presence || {}).to_json
   .form-row
     .form-label= f.label :parent_id
     .form-field= f.select :parent_id, tree_options_for_select(Page.full_tree(@page.locale || Page.locales.first), exclude: @page.id, selected: @page.parent_id), include_blank: ' -- '