feat: add hk::Dataset::deSerializeWithValidityBlob

- Counterpart of serializing with validity blob: sets each member's validity from the blob
- Checks the stream length up front, a short stream leaves the dataset untouched
- deSerialize keeps ignoring the blob

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

unittests/datapool/testDataset.cpp

@@ -82,4 +82,52 @@ TEST_CASE("Pool Dataset Test", "[datapool]") {
     CHECK(buf[31] == 0b10000000);
     CHECK(buf[32] == 0);
   }
+
+  SECTION("Pool Dataset Deserialization With Validity") {
+    uint8_t buf[64]{};
+    TestDatasetLarger source;
+    source.setChildrenValidity(true);
+    source.test1 = 502392;
+    source.test1.setValid(false);
+    source.test7 = -5;
+    source.test8.entry[1] = 1234;
+    source.test8.setValid(false);
+    source.serializeWithValidityBlob = true;
+    size_t serLen = 0;
+    uint8_t* dataPtr = buf;
+    REQUIRE(source.serialize(&dataPtr, &serLen, sizeof(buf), SerializeIF::Endianness::NETWORK) ==
+            returnvalue::OK);
+
+    TestDatasetLarger target;
+    target.setChildrenValidity(true);
+    const uint8_t* readPtr = buf;
+    size_t remaining = serLen;
+    CHECK(target.deSerializeWithValidityBlob(&readPtr, &remaining,
+                                             SerializeIF::Endianness::NETWORK) == returnvalue::OK);
+    CHECK(remaining == 0);
+    CHECK(readPtr == buf + serLen);
+    CHECK(target.test0.isValid());
+    CHECK(!target.test1.isValid());
+    CHECK(target.test1.get() == 502392);
+    CHECK(target.test7.isValid());
+    CHECK(target.test7.get() == -5);
+    CHECK(!target.test8.isValid());
+    CHECK(target.test8.entry[1] == 1234);
+  }
+
+  SECTION("Pool Dataset Deserialization With Validity Short Stream") {
+    uint8_t buf[64]{};
+    TestDatasetSmall target;
+    target.test0 = 7;
+    target.test0.setValid(true);
+    const uint8_t* readPtr = buf;
+    // One byte short of the 5 value bytes and the 1 byte validity blob
+    size_t remaining = 5;
+    CHECK(target.deSerializeWithValidityBlob(&readPtr, &remaining,
+                                             SerializeIF::Endianness::NETWORK) ==
+          SerializeIF::STREAM_TOO_SHORT);
+    CHECK(remaining == 5);
+    CHECK(target.test0.get() == 7);
+    CHECK(target.test0.isValid());
+  }
 }