fix(ocr): force HTTP/1.1 on RestClient to OCR service

JDK HttpClient defaults to HTTP/2 with upgrade negotiation. Uvicorn
rejects the upgrade ('Unsupported upgrade request'), causing the
request body to be lost and a 422 'Field required' from FastAPI.
Force HTTP/1.1 since the OCR service is internal and doesn't need h2.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/service/RestClientOcrClient.java

@@ -23,6 +23,7 @@ public class RestClientOcrClient implements OcrClient, OcrHealthClient {
 
     public RestClientOcrClient(@Value("${app.ocr.base-url:http://ocr-service:8000}") String baseUrl) {
         HttpClient httpClient = HttpClient.newBuilder()
+                .version(HttpClient.Version.HTTP_1_1)
                 .connectTimeout(Duration.ofSeconds(10))
                 .build();
         JdkClientHttpRequestFactory requestFactory = new JdkClientHttpRequestFactory(httpClient);