Remove SimpleFin demo file with outdated setup token

app/models/provider/simplefin/demo.rb

@@ -1,34 +0,0 @@
-class Provider::Simplefin::Demo
-  # Demo setup token from SimpleFin documentation
-  DEMO_TOKEN = "aHR0cHM6Ly9icmlkZ2Uuc2ltcGxlZmluLm9yZy9zaW1wbGVmaW4vY2xhaW0vZGVtbw=="
-
-  def self.test_connection
-    provider = Provider::Simplefin.new
-
-    begin
-      # Claim the demo token
-      access_url = provider.claim_access_url(DEMO_TOKEN)
-      puts "✓ Successfully claimed access URL: #{access_url[0..50]}..."
-
-      # Get account data
-      accounts_data = provider.get_accounts(access_url)
-      puts "✓ Successfully retrieved accounts data"
-      puts "  - Accounts count: #{accounts_data[:accounts]&.count || 0}"
-      puts "  - Errors: #{accounts_data[:errors] || 'None'}"
-
-      if accounts_data[:accounts]&.any?
-        account = accounts_data[:accounts].first
-        puts "  - First account: #{account[:name]} (#{account[:currency]}) - Balance: #{account[:balance]}"
-        puts "  - Transactions: #{account[:transactions]&.count || 0}"
-      end
-
-      true
-    rescue Provider::Simplefin::SimplefinError => e
-      puts "✗ SimpleFin error: #{e.message} (#{e.error_type})"
-      false
-    rescue => e
-      puts "✗ Unexpected error: #{e.message}"
-      false
-    end
-  end
-end