feat: implement payout system database schema and models

db/migrate/20250916215130_update_payout_status_on_events.rb

@@ -0,0 +1,11 @@
+class UpdatePayoutStatusOnEvents < ActiveRecord::Migration[8.0]
+  def up
+    change_column_default :events, :payout_status, from: nil, to: 0
+    add_index :events, :payout_status
+  end
+
+  def down
+    change_column_default :events, :payout_status, from: 0, to: nil
+    remove_index :events, :payout_status
+  end
+end