Add rake task to export submission counts to CloudWatch

Add metrics:export_submission_counts for scheduled KPI publishing.

Author: theseanything

lib/tasks/metrics.rake

@@ -0,0 +1,6 @@
+namespace :metrics do
+  desc "Export submission counts to CloudWatch metrics grouped by form"
+  task export_submission_counts: :environment do
+    Metrics::SubmissionCountService.new.publish_submission_counts
+  end
+end

spec/lib/tasks/metrics.rake_spec.rb

@@ -0,0 +1,17 @@
+require "rails_helper"
+
+RSpec.describe "metrics.rake", type: :task do
+  describe "metrics:export_submission_counts" do
+    subject(:task) do
+      Rake::Task["metrics:export_submission_counts"]
+    end
+
+    it "publishes submission counts via Metrics::SubmissionCountService" do
+      service = instance_double(Metrics::SubmissionCountService)
+      allow(Metrics::SubmissionCountService).to receive(:new).and_return(service)
+      expect(service).to receive(:publish_submission_counts)
+
+      task.invoke
+    end
+  end
+end