Add party enum field to Event component

Add new party field to Event component with agent and customer values
to specify the party submitting the transaction. Includes comprehensive
test coverage and documentation updates.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: horgh

CHANGELOG.md

@@ -7,6 +7,9 @@
   version 2.8.0 of this gem.
 * Added `/event/type` values `:credit_application` and `:fund_transfer` to
   `Minfraud::Components::Event`.
+* Added the input `/event/party`. This is the party submitting the
+  transaction. You may provide this using the `party` attribute on
+  `Minfraud::Components::Event`.
 
 ## v2.8.0 (2025-05-23)
 

README.md

@@ -86,6 +86,7 @@ assessment = Minfraud::Assessments.new(
     user_agent:      'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36',
   },
   event: {
+    party:          :customer,
     transaction_id: 'txn3134133',
     shop_id:        's2123',
     time:           '2012-04-12T23:20:50+00:00',

lib/minfraud/components/event.rb

@@ -9,6 +9,18 @@ class Event < Base
       include ::Minfraud::Enum
       include Minfraud::Validates
 
+      # The party submitting the transaction. This must be one of +:agent+ or
+      # +:customer+.
+      #
+      # @!attribute party
+      #
+      # @return [Symbol, nil]
+      enum_accessor :party,
+                    %i[
+                      agent
+                      customer
+                    ]
+
       # Your internal ID for the transaction. MaxMind can use this to locate a
       # specific transaction in logs, and it will also show up in email alerts
       # and notifications from MaxMind to you. No specific format is required.
@@ -61,6 +73,7 @@ class Event < Base
       # @param params [Hash] Hash of parameters. Each key/value should
       #   correspond to one of the available attributes.
       def initialize(params = {})
+        self.party      = params[:party]
         @transaction_id = params[:transaction_id]
         @shop_id        = params[:shop_id]
         @time           = params[:time]

spec/components/event_spec.rb

@@ -11,6 +11,14 @@
         end.to raise_exception(Minfraud::NotEnumValueError)
       end
     end
+
+    context 'with an invalid party' do
+      it 'raises an exception' do
+        expect do
+          described_class.new({ party: :invalid })
+        end.to raise_exception(Minfraud::NotEnumValueError)
+      end
+    end
   end
 
   describe 'validation' do
@@ -43,5 +51,17 @@
         type: :fund_transfer,
       )
     end
+
+    it 'accepts agent as a valid party' do
+      described_class.new(
+        party: :agent,
+      )
+    end
+
+    it 'accepts customer as a valid party' do
+      described_class.new(
+        party: :customer,
+      )
+    end
   end
 end