fix(outages): format numeric portal dates as integers

Portal date fields arrive as numbers; fmt's %v rendered them in scientific
notation, so the "current outage" filter could not parse them and kept past
outages (a 'Прошлые' record leaked through). Format integer-valued attributes
explicitly.

internal/adapters/arcgis/client.go

@@ -191,14 +191,22 @@ func codeKey(v any) string {
 	}
 }
 
+// stringOf renders an attribute value as a string. The important case is
+// numeric dates: fmt's %v turns a float64 into scientific notation ("1.79e+12")
+// which the date parser cannot read, so integers are formatted explicitly.
 func stringOf(v any) string {
-	if s, ok := v.(string); ok {
+	switch t := v.(type) {
-		return s
+	case nil:
-	}
-	if v == nil {
 		return ""
-	}
+	case string:
+		return t
+	case float64:
+		return strconv.FormatInt(int64(t), 10)
+	case json.Number:
+		return t.String()
+	default:
 		return fmt.Sprintf("%v", v)
+	}
 }
 
 // actionFor maps a portal system name to the canonical action code used by the

internal/adapters/arcgis/client_test.go

@@ -94,6 +94,24 @@ func TestQueryStripsDistrictSuffix(t *testing.T) {
 	}
 }
 
+// TestQueryFormatsNumericDates guards against scientific notation in dates,
+// which broke the "current outage" filter.
+func TestQueryFormatsNumericDates(t *testing.T) {
+	const env = `{"features":[{"value":"Ленина улица, 1","attributes":{"address":"Ленина улица, 1","start_date":1790820000000,"end_date":1791799200000}}]}`
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write([]byte(env))
+	}))
+	defer ts.Close()
+
+	rows, err := New(ts.URL, time.Second, 0).Query(context.Background(), "Ленина улица 1")
+	if err != nil {
+		t.Fatalf("Query: %v", err)
+	}
+	if rows[0].StartDate != "1790820000000" || rows[0].EndDate != "1791799200000" {
+		t.Errorf("numeric dates must be integer-formatted: %q..%q", rows[0].StartDate, rows[0].EndDate)
+	}
+}
+
 // TestLikePattern guards the ordinal/house padding rule: padding an ordinal
 // that starts the string breaks the portal match.
 func TestLikePattern(t *testing.T) {