bingo: optional prose per datacenter page

The datacenter pages carry only generated sentences, which is thin
content to rank on. Migration 015 adds about_ru/en/uk, edited in the
admin form and rendered as paragraphs below the facts.

There is deliberately no fallback to ru: Russian prose on the English
page would hurt more than an absent paragraph.

Assisted-by: Claude:opus-5

db/migrations/015_bingo_about.rb

@@ -0,0 +1,7 @@
+Sequel.migration do
+  change do
+    # Optional prose for the datacenter page, per locale. No fallback to ru:
+    # Russian text on the en page would be worse than none.
+    %w[ru en uk].each { |l| add_column :bingo_datacenters, :"about_#{l}", String, text: true }
+  end
+end

lib/bingo.rb

@@ -143,6 +143,11 @@ module Bingo
       key.delete_prefix(Photo::PREFIX)
     end
 
+    # Paragraphs of the datacenter page's prose in exactly this locale.
+    def about(locale)
+      self[:"about_#{locale}"].to_s.strip.split(/\n\s*\n/).map(&:strip)
+    end
+
     # 1200x630 JPEG for og:image (every preview client renders it); the
     # webp dialog variant until it exists.
     def og_file

lib/bingo_admin.rb

@@ -4,7 +4,7 @@ require 'uri'
 # Registered into AsxpioWeb, so AdminAuth (HTTP Basic) and CSRF apply.
 module BingoAdmin
   DC_TEXT = %w[name_ru name_en name_uk city_ru city_en city_uk operator mw mw_type status
-               photo_credit photo_source_url info_url].freeze
+               photo_credit photo_source_url info_url about_ru about_en about_uk].freeze
 
   module Helpers
     def bingo_public_url

test/bingo_test.rb

@@ -252,6 +252,16 @@ class BingoTest < Minitest::Test
     refute_includes last_response.body, 'rel="prev"'
   end
 
+  def test_dc_about_text
+    @app = AsxpioWeb
+    token = admin_token("/admin/bingo/dc/#{@dcs[1].id}")
+    post "/admin/bingo/dc/#{@dcs[1].id}", dc_params(authenticity_token: token, about_en: "First <b>para</b>.\r\n\r\nSecond."), admin_env
+    assert_equal "First <b>para</b>.\r\n\r\nSecond.", @dcs[1].refresh.about_en
+    public = Rack::MockRequest.new(BingoWeb) # rack-test's session is bound to AsxpioWeb now
+    assert_includes public.get('/en/dc/dc-2').body, '<p class="facts">First &lt;b&gt;para&lt;/b&gt;.</p><p class="facts">Second.</p>'
+    refute_includes public.get('/ru/dc/dc-2').body, 'Second.' # no fallback across languages
+  end
+
   def test_reserve_dc_has_a_page
     Bingo::Datacenter.create(slug: 'dc-26', position: 26, name_ru: 'ЦОД 26', city_ru: 'Тверь', operator: 'Op')
     get '/ru/dc/dc-26'

views/admin/bingo/edit.erb

@@ -65,6 +65,9 @@
         <div class="field"><label for="photo_credit">Photo credit</label><input type="text" id="photo_credit" name="photo_credit" value="<%= @dc.photo_credit %>" /></div>
         <div class="field"><label for="photo_source_url">Photo source URL</label><input type="url" id="photo_source_url" name="photo_source_url" value="<%= @dc.photo_source_url %>" /></div>
         <div class="field"><label for="info_url">Info / fact source URL</label><input type="url" id="info_url" name="info_url" value="<%= @dc.info_url %>" /></div>
+        <% %w[ru en uk].each do |l| %>
+            <div class="field"><label for="about_<%= l %>">About (<%= l %>) <span class="optional">(datacenter page; blank lines split paragraphs; not translated automatically, blank = hidden)</span></label><textarea id="about_<%= l %>" name="about_<%= l %>" rows="4" maxlength="5000"><%= @dc[:"about_#{l}"] %></textarea></div>
+        <% end %>
         <% if can?('bingo', 'write') %><button type="submit" class="download-button"><%= fresh ? 'Add datacenter' : 'Save' %></button><% end %>
         </fieldset>
     </form>

views/bingo/dc.erb

@@ -14,6 +14,7 @@
     <h1><%= dc.l(:name, @locale) %></h1>
     <%== erb :_dc_meta, layout: false, locals: { dc: dc } %>
     <p class="facts"><%= dc_facts(dc).join(' ') %></p>
+    <% dc.about(@locale).each do |para| %><p class="facts"><%= para %></p><% end %>
     <section>
       <h2><%= t(:incidents) %></h2>
       <%== erb :_dc_incidents, layout: false, locals: { dc: dc } %>