feat: sync visible product branding

Sync telesrv c779c48 (feat(branding): unify visible product naming).

Skipped private www files and preserved public README files; mapped orange appearance seed names to public default names.

internal/domain/branding_test.go

@@ -0,0 +1,20 @@
+package domain
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestServiceIdentityAndLoginMessageUseTelesrvBrand(t *testing.T) {
+	serviceUser := OfficialSystemUser()
+	if serviceUser.FirstName != "Telesrv" || serviceUser.Username != "telesrv" {
+		t.Fatalf("service user = %+v, want Telesrv identity", serviceUser)
+	}
+	message, err := OfficialLoginCodeMessage(42, "12345", 1)
+	if err != nil {
+		t.Fatalf("build login message: %v", err)
+	}
+	if !strings.Contains(message.Body, "Telesrv") || strings.Contains(strings.ToLower(message.Body), "telegram") {
+		t.Fatalf("login message exposes wrong brand: %q", message.Body)
+	}
+}