fix: accept the German W as a gender on the application endpoint

tests/Controller/Api/ApplicationFormControllerTest.php

@@ -359,6 +359,50 @@ class ApplicationFormControllerTest extends WebTestCase
         }
     }
 
+    /**
+     * The German spelling of female. The forms are German and some of them post W; it is accepted
+     * and stored as F, so the row, the provisioned teamer and the payload all read the same
+     * whichever spelling arrived.
+     */
+    public function testTheGermanWIsAcceptedAndStoredAsF(): void
+    {
+        $this->post(['gender' => 'W'] + $this->payload());
+
+        $this->assertSame(Response::HTTP_ACCEPTED, $this->client->getResponse()->getStatusCode());
+
+        $submission = $this->lastSubmission();
+
+        $this->assertSame('F', $submission->getGender());
+        $this->assertSame('W', $submission->toPayload()['geschlecht']);
+        $this->assertSame('W', $submission->getPayload()['gender'] ?? null);
+    }
+
+    /**
+     * Case is the sender's business, not a reason to lose an application: every spelling a form
+     * can post lands on the same stored value.
+     *
+     * @dataProvider genderSpellings
+     */
+    public function testAGenderIsReadWhateverItsCase(string $posted, string $stored): void
+    {
+        $this->post(['gender' => $posted] + $this->payload());
+
+        $this->assertSame(Response::HTTP_ACCEPTED, $this->client->getResponse()->getStatusCode());
+        $this->assertSame($stored, $this->lastSubmission()->getGender());
+    }
+
+    /**
+     * @return iterable<string, array{string, string}>
+     */
+    public static function genderSpellings(): iterable
+    {
+        yield 'lowercase f' => ['f', 'F'];
+        yield 'lowercase w' => ['w', 'F'];
+        yield 'lowercase m' => ['m', 'M'];
+        yield 'lowercase d' => ['d', 'D'];
+        yield 'padded' => [' W ', 'F'];
+    }
+
     /**
      * The mapped vocabulary grows on the website side without a release here. An unknown key is
      * ignored, and kept in the raw payload so it can be mapped later without losing the answers