feat(lifecycle): add EventResolver service

Pure function mapping reservation events to timestamps; used by Scheduler (T9) to compute fire_at.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

enterprise/app/services/captain/lifecycle/event_resolver.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+class Captain::Lifecycle::EventResolver
+  UNSUPPORTED_IN_MVP = %w[checkin.detected checkout.detected].freeze
+
+  def self.resolve(reservation, event_name)
+    return nil if UNSUPPORTED_IN_MVP.include?(event_name)
+
+    case event_name
+    when 'reservation.confirmed'
+      reservation.updated_at
+    when 'checkin.scheduled_at'
+      reservation.check_in_at
+    when 'checkout.scheduled_at'
+      reservation.check_out_at
+    when 'reservation.cancelled'
+      reservation.updated_at if reservation.status.to_s == 'cancelled'
+    when 'reservation.no_show'
+      reservation.check_in_at&.+(1.hour)
+    else
+      raise ArgumentError, "unknown event: #{event_name.inspect}"
+    end
+  end
+end

spec/enterprise/services/captain/lifecycle/event_resolver_spec.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Captain::Lifecycle::EventResolver do
+  let(:reservation) do
+    build(:captain_reservation,
+          check_in_at: Time.zone.parse('2026-04-20 22:00:00'),
+          check_out_at: Time.zone.parse('2026-04-21 12:00:00'),
+          updated_at: Time.zone.parse('2026-04-19 10:00:00'))
+  end
+
+  describe '.resolve' do
+    it 'returns check_in_at for checkin.scheduled_at' do
+      expect(described_class.resolve(reservation, 'checkin.scheduled_at'))
+        .to eq(reservation.check_in_at)
+    end
+
+    it 'returns check_out_at for checkout.scheduled_at' do
+      expect(described_class.resolve(reservation, 'checkout.scheduled_at'))
+        .to eq(reservation.check_out_at)
+    end
+
+    it 'returns updated_at for reservation.confirmed' do
+      expect(described_class.resolve(reservation, 'reservation.confirmed'))
+        .to eq(reservation.updated_at)
+    end
+
+    it 'returns nil for checkin.detected (not yet supported)' do
+      expect(described_class.resolve(reservation, 'checkin.detected')).to be_nil
+    end
+
+    it 'returns nil for checkout.detected (not yet supported)' do
+      expect(described_class.resolve(reservation, 'checkout.detected')).to be_nil
+    end
+
+    it 'raises for unknown event' do
+      expect { described_class.resolve(reservation, 'unknown.event') }
+        .to raise_error(ArgumentError, /unknown event/)
+    end
+  end
+end