fix: anchor growth forecasts to real Tehran date

internal/eventcatalog/catalog_test.go

@@ -0,0 +1,39 @@
+package eventcatalog
+
+import (
+	"testing"
+	"time"
+)
+
+func TestResolveBlackFridayUsesRecurrenceRule(t *testing.T) {
+	t.Parallel()
+
+	got, err := ResolveRecurrence(RecurrenceBlackFriday, 2026, time.UTC)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := "2026-11-27"; got.Format(time.DateOnly) != want {
+		t.Fatalf("Black Friday = %s, want %s", got.Format(time.DateOnly), want)
+	}
+}
+
+func TestValidateEventsDistinguishesCelebrationAndMourning(t *testing.T) {
+	t.Parallel()
+
+	events := []Event{
+		{ID: "nowruz-1405", TitleFA: "نوروز", StartDate: "2026-03-21", EndDate: "2026-03-24", Type: TypeCultural, Tone: ToneCelebratory, CommercialPosture: PosturePromote, SourceURI: "https://calendar.ut.ac.ir/", SourceVersion: "1405", InclusionRationale: "تقویم رسمی", GeographicScope: "IR", RelevanceBPS: 10000, ConfidenceBPS: 10000},
+		{ID: "ashura-1405", TitleFA: "عاشورای حسینی", StartDate: "2026-06-25", EndDate: "2026-06-25", Type: TypeReligious, Tone: ToneMourning, CommercialPosture: PostureNoPromotion, SourceURI: "https://calendar.ut.ac.ir/", SourceVersion: "1405", InclusionRationale: "تقویم رسمی", GeographicScope: "IR", RelevanceBPS: 10000, ConfidenceBPS: 10000},
+	}
+	if err := ValidateEvents(events); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestValidateEventsRejectsPromotionalMourningEvent(t *testing.T) {
+	t.Parallel()
+
+	event := Event{ID: "mourning", TitleFA: "یادبود", StartDate: "2026-01-01", EndDate: "2026-01-01", Type: TypeCultural, Tone: ToneMourning, CommercialPosture: PosturePromote, SourceURI: "https://example.test", SourceVersion: "v1", InclusionRationale: "reviewed", GeographicScope: "IR", RelevanceBPS: 10000, ConfidenceBPS: 10000}
+	if err := ValidateEvents([]Event{event}); err == nil {
+		t.Fatal("expected mourning promotion validation error")
+	}
+}