fix: give chatbot pickups per-leg surcharges including the return leg

tests/Service/ProductExportBuilderTest.php

@@ -159,6 +159,8 @@ class ProductExportBuilderTest extends TestCase
             'city' => 'Stadt 4',
             'street' => 'Strasse 4',
             'price' => 5.9,
+            'returnLeg' => false,
+            'returnPrice' => null,
             'datetime' => '2026-12-03T23:30:00',
         ], $pickups[0]);
         self::assertNull($pickups[1]['price'], 'an absent price is null');
@@ -167,6 +169,15 @@ class ProductExportBuilderTest extends TestCase
         self::assertNull($pickups[2]['code']);
     }
 
+    public function testJoinsEachPickupWithItsReturnLegVerbatim(): void
+    {
+        $pickups = $this->rowFor('900-222931')['pickups'];
+
+        self::assertSame([false, true, true, false], array_column($pickups, 'returnLeg'));
+        self::assertSame(3.0, $pickups[1]['returnPrice']);
+        self::assertNull($pickups[2]['returnPrice'], 'listed on the return leg without a price');
+    }
+
     public function testPickupTimesInTheSpringForwardGapAreNotShifted(): void
     {
         // DPWUSMP280327 in the 30.09.2026 13:11 export. Berlin skips 02:00-02:59 that night.