feat: ground competitive insights in peer metrics

internal/insight/builder_transaction_test.go

@@ -3,6 +3,8 @@ package insight
 import (
 	"strings"
 	"testing"
+
+	"git.amiirkhl.ir/starcoach-hackathon/zarinpal-analytics-backend/internal/peercomparison"
 )
 
 func TestDeterministicTransactionCopyDistinguishesPaymentStatesWithoutCausalClaims(t *testing.T) {
@@ -27,6 +29,22 @@ func TestDeterministicTransactionCopyDistinguishesPaymentStatesWithoutCausalClai
 	}
 }
 
+func TestDeterministicPeerCopyNamesStrongestWeakestAndAction(t *testing.T) {
+	result := peercomparison.Result{State: peercomparison.StateReady, Metrics: []peercomparison.Metric{
+		{MetricID: "payment_success_rate", MerchantPerformancePercentile: "85.00"},
+		{MetricID: "verification_completion_rate", MerchantPerformancePercentile: "40.00"},
+	}}
+	copy := deterministicPeerCopy(&result, "مرداد ۱۴۰۵")
+	for _, expected := range []string{"مرداد ۱۴۰۵", "موفقیت پرداخت", "صدک 85.00", "تکمیل تأیید", "صدک 40.00"} {
+		if !strings.Contains(copy.LatestObserved.Body, expected) {
+			t.Fatalf("peer summary missing %q: %s", expected, copy.LatestObserved.Body)
+		}
+	}
+	if !strings.Contains(copy.Options[0].Description, "تکمیل تأیید") {
+		t.Fatalf("peer action did not target weakest category: %+v", copy.Options)
+	}
+}
+
 func TestDeterministicTransactionCopyHandlesEmptyPeriod(t *testing.T) {
 	copy := deterministicTransactionCopy(
 		PeriodScope{JalaliLabelFA: "امروز"},