add jackson identity passthrough for unchanged lazy values

fixes #2

Author: stalep

jjq-jackson/src/main/java/io/hyperfoil/tools/jjq/jackson/JacksonConverter.java

@@ -101,6 +101,10 @@ public static JsonNode toJsonNode(JqValue value) {
      * for node creation.
      */
     public static JsonNode toJsonNode(JqValue value, ObjectMapper mapper) {
+        JsonNode original = LazyJacksonConverter.originalNodeIfLazy(value);
+        if (original != null) {
+            return original;
+        }
         return switch (value) {
             case JqNull ignored -> NullNode.getInstance();
             case JqBoolean b -> BooleanNode.valueOf(b.booleanValue());

jjq-jackson/src/test/java/io/hyperfoil/tools/jjq/jackson/JacksonConverterTest.java

@@ -165,4 +165,13 @@ void roundTrip() throws Exception {
         assertEquals(original, restored);
     }
 
+    @Test
+    void lazyIdentityPassthroughReturnsOriginalNode() throws Exception {
+        JsonNode original = MAPPER.readTree("{\"name\":\"Alice\",\"age\":30}");
+        JqValue lazy = JacksonConverter.fromJsonNodeLazy(original);
+
+        JsonNode restored = JacksonConverter.toJsonNode(lazy);
+        assertSame(original, restored);
+    }
+
 }

jjq-jackson/src/test/java/io/hyperfoil/tools/jjq/jackson/LazyJacksonConverterTest.java

@@ -131,6 +131,19 @@ void toJsonNodeDoesNotForceFullLazyObjectMaterialization() throws Exception {
         assertEquals(1, LazyJacksonConverter.convertedEntryCount(lazy));
     }
 
+    @Test
+    void identityPassthroughAfterSingleFieldAccess() throws Exception {
+        JsonNode node = MAPPER.readTree("{\"a\":1,\"b\":2,\"c\":3}");
+        JqObject lazy = (JqObject) JacksonConverter.fromJsonNodeLazy(node);
+
+        assertEquals(JqNumber.of(2), lazy.get("b"));
+        JsonNode restored = JacksonConverter.toJsonNode(lazy);
+
+        assertSame(node, restored);
+        assertFalse(LazyJacksonConverter.isFullyConverted(lazy));
+        assertEquals(1, LazyJacksonConverter.convertedEntryCount(lazy));
+    }
+
     @Test
     void toJsonStringWorks() throws Exception {
         JsonNode node = MAPPER.readTree("{\"a\":1,\"b\":[2,3]}");