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

views/admin/bingo/edit.erb

@@ -45,6 +45,13 @@
                 <div class="field"><label for="city_<%= l %>">City (<%= l %>)</label><input type="text" id="city_<%= l %>" name="city_<%= l %>" value="<%= @dc[:"city_#{l}"] %>" <%= 'required' if l == 'ru' %> /></div>
             <% end %>
             <div class="field"><label for="operator">Operator</label><input type="text" id="operator" name="operator" value="<%= @dc.operator %>" required /></div>
+            <div class="field">
+                <label for="provider">Provider <span class="optional">(groups the per-provider card)</span></label>
+                <select id="provider" name="provider">
+                    <option value="" <%= 'selected' unless @dc.provider %>>none</option>
+                    <% Bingo::PROVIDERS.each do |slug, names| %><option value="<%= slug %>" <%= 'selected' if @dc.provider == slug %>><%= names['ru'] %></option><% end %>
+                </select>
+            </div>
             <div class="field"><label for="mw">MW <span class="optional">(number or range)</span></label><input type="text" id="mw" name="mw" value="<%= @dc.mw %>" /></div>
             <div class="field">
                 <label for="mw_type">Capacity type</label>

views/bingo/index.erb

@@ -17,6 +17,20 @@
   </header>
 
   <p class="lead"><%= t(:desc) %></p>
+  <% provs = Bingo::Board.providers(@view) %>
+  <form class="providers" method="get" action="/<%= @locale %>">
+    <% if @view == 'all' %><input type="hidden" name="view" value="all"><% end %>
+    <fieldset>
+      <legend><%= t(:providers_label) %></legend>
+      <% provs.each do |slug, total, crossed| %>
+        <label><input type="checkbox" name="p[]" value="<%= slug %>" <%= 'checked' if @providers.include?(slug) %>> <%= Bingo.provider_name(slug, @locale) %> <span><%= crossed %>/<%= total %></span></label>
+      <% end %>
+    </fieldset>
+    <div class="provider-actions">
+      <button type="submit"><%= t(:providers_apply) %></button>
+      <% if @board.filtered? %><a href="<%= card_path(@locale, @view, []) %>"><%= t(:providers_reset) %></a><% end %>
+    </div>
+  </form>
   <p class="meta">
     <%= t(:crossed) %> <b><%= b.hit.count(true) %></b>/<%= b.cells.size %>
     · <%= t(:lines) %> <b><%= b.wins.size %></b>
@@ -48,6 +62,7 @@
         <% if b.hit[idx] %><div class="stamp"><%= kind_icon(dc.incidents.first.kind) %></div><% end %>
       </a>
     <% end %>
+    <% (b.cells.size...Bingo::SIZE**2).each do %><div class="cell empty" aria-hidden="true"></div><% end %>
   </div>
 
   <section>

views/bingo/layout.erb

@@ -81,6 +81,16 @@
   .banner { margin: 0 0 16px; padding: 12px 16px; border-radius: 10px; background: var(--win); color: var(--on-win); font-weight: 700; font-size: 18px; }
 
   .letters, .grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 6px; }
+  .cell.empty { background: transparent; border-style: dashed; cursor: default; }
+  .providers { margin: 0 0 16px; }
+  .providers fieldset { border: 0; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 6px; }
+  .providers legend { font-size: 13px; color: var(--muted); margin-bottom: 6px; padding: 0; }
+  .providers label { display: inline-flex; align-items: center; gap: 6px; padding: 3px 10px; border: 1px solid var(--line); border-radius: 999px; font-size: 13px; cursor: pointer; white-space: nowrap; }
+  .providers label:has(input:checked) { border-color: var(--ink); }
+  .providers input { accent-color: var(--hit); margin: 0; }
+  .providers label span { color: var(--muted); font-variant-numeric: tabular-nums; }
+  .provider-actions { display: flex; gap: 12px; align-items: center; margin-top: 8px; font-size: 13px; }
+  .provider-actions button { font: inherit; padding: 3px 12px; border-radius: 6px; border: 1px solid var(--line); background: var(--card); color: var(--ink); cursor: pointer; }
   .letters div { text-align: center; font-weight: 900; font-size: clamp(22px, 5vw, 36px); color: var(--hit); }
   .grid { margin-top: 6px; }
   .cell {