feat: Preserve OpenAPI extensions on Info

Author: thced

src/main/java/com/retailsvc/http/spec/Info.java

@@ -1,3 +1,5 @@
 package com.retailsvc.http.spec;
 
-public record Info(String title, String version) {}
+import java.util.Map;
+
+public record Info(String title, String version, Map<String, Object> extensions) {}

src/main/java/com/retailsvc/http/spec/Spec.java

@@ -100,7 +100,7 @@ private static String stripPrefix(String ref, String prefix) {
   }
 
   private static Info parseInfo(Map<String, Object> raw) {
-    return new Info((String) raw.get("title"), (String) raw.get("version"));
+    return new Info((String) raw.get("title"), (String) raw.get("version"), extractExtensions(raw));
   }
 
   private static List<Server> parseServers(List<Map<String, Object>> raw) {

src/test/java/com/retailsvc/http/internal/RequestPreparationFilterTest.java

@@ -45,7 +45,7 @@ private HttpExchange exchange(String method, String path, byte[] body) {
   private Spec specWith(Operation... ops) {
     return new Spec(
         "3.1.0",
-        new Info("t", "1"),
+        new Info("t", "1", Map.of()),
         List.of(new Server("/")),
         List.of(ops),
         Map.of(),

src/test/java/com/retailsvc/http/spec/ExtensionsTest.java

@@ -41,4 +41,20 @@ void specExtensionsEmptyWhenNoXKeys() {
     Spec spec = Spec.from(raw);
     assertThat(spec.extensions()).isEmpty();
   }
+
+  @Test
+  void infoExtensionsExposeXKeys() {
+    Map<String, Object> raw =
+        Map.of(
+            "openapi",
+            "3.1.0",
+            "info",
+            Map.of("title", "t", "version", "1", "x-contact-team", "platform"),
+            "servers",
+            List.of(Map.of("url", "https://example.com")),
+            "paths",
+            Map.of());
+    Spec spec = Spec.from(raw);
+    assertThat(spec.info().extensions()).containsEntry("x-contact-team", "platform");
+  }
 }

src/test/java/com/retailsvc/http/spec/SpecRecordsTest.java

@@ -33,7 +33,7 @@ void serverHasUrl() {
 
   @Test
   void infoHasTitleAndVersion() {
-    Info i = new Info("test", "1.0.0");
+    Info i = new Info("test", "1.0.0", Map.of());
     assertThat(i.title()).isEqualTo("test");
     assertThat(i.version()).isEqualTo("1.0.0");
   }