bingo: build the card from chosen providers

Let visitors tick providers (Yandex, IXcellerate, RTK-DC, Sber, …) and
get the usual 5×5 card made of only those providers' datacenters, first
25 in ranking order, with lines scored as normal. A selection with fewer
than 25 sites leaves the rest of the card empty, so the card is always
5×5. Each provider chip shows crossed/total for the current view.

Datacenters get a provider slug, backfilled from the free-text operator,
guessed for new rows and editable in the admin. Filtered URLs are
noindex with canonical to the plain card.

Assisted-by: Claude:opus-5

db/migrations/016_bingo_provider.rb

@@ -0,0 +1,23 @@
+Sequel.migration do
+  up do
+    # Company grouping for the per-provider cards (Bingo::PROVIDERS slugs).
+    # Backfilled from the free-text operator; Datacenter#before_create keeps
+    # new rows filled the same way (Bingo.guess_provider).
+    add_column :bingo_datacenters, :provider, String
+    {
+      'yandex' => %w[Яндекс%], 'ixcellerate' => %w[IXcellerate%], 'rtk' => %w[РТК-ЦОД%],
+      'atomdata' => %w[Атомдата% Росатом%], 'datapro' => %w[DataPro%], 'selectel' => %w[Selectel%],
+      'mws' => %w[MWS% МТС%], 'keypoint' => ['Key Point%'], '3data' => %w[3data%], 'sber' => %w[Сбер%],
+      'megafon' => %w[МегаФон%], 'datahouse' => %w[DataHouse%], 'oxygen' => %w[OXYGEN%], 'linx' => %w[Linx%],
+      'cloudx' => ['Cloud X%'], 'nkgroup' => ['NK Group%'], 'goznak' => %w[Гознак%]
+    }.each do |slug, patterns|
+      patterns.each do |pat|
+        self[:bingo_datacenters].where(provider: nil).where(Sequel.ilike(:operator, pat)).update(provider: slug)
+      end
+    end
+  end
+
+  down do
+    drop_column :bingo_datacenters, :provider
+  end
+end