fix: make sponsor coach spots nil-safe

app/models/sponsor.rb

@@ -53,7 +53,9 @@ class Sponsor < ApplicationRecord
   mount_uploader(:avatar, AvatarUploader)
 
   def coach_spots
-    number_of_coaches || (seats / 2.0).round
+    return number_of_coaches if number_of_coaches.present?
+
+    seats.present? ? (seats / 2.0).round : nil
   end
 
   def self.latest

spec/models/sponsor_spec.rb

@@ -64,4 +64,24 @@
         .with_values(%i[hidden standard bronze silver gold community])
     end
   end
+
+  describe '#coach_spots' do
+    it 'returns number_of_coaches when present' do
+      sponsor = Fabricate.build(:sponsor, number_of_coaches: 4, seats: 10)
+
+      expect(sponsor.coach_spots).to eq(4)
+    end
+
+    it 'falls back to half the seats rounded' do
+      sponsor = Fabricate.build(:sponsor, number_of_coaches: nil, seats: 15)
+
+      expect(sponsor.coach_spots).to eq(8)
+    end
+
+    it 'does not raise when both seats and number_of_coaches are missing' do
+      sponsor = Fabricate.build(:sponsor, number_of_coaches: nil, seats: nil)
+
+      expect(sponsor.coach_spots).to be_nil
+    end
+  end
 end