Expose vector values from Int7SQVectorScorerSupplier (#136416) (#136530)

Exposes the vector values from the Int7 scorer supplier, via a "capability" interface (same pattern as used elsewhere in Lucene, e.g. MemorySegmentAccess or HasIndexSlice)

Author: ldematte

libs/simdvec/src/main/java/org/elasticsearch/simdvec/QuantizedByteVectorValuesAccess.java

@@ -0,0 +1,16 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.simdvec;
+
+import org.apache.lucene.util.quantization.QuantizedByteVectorValues;
+
+public interface QuantizedByteVectorValuesAccess {
+    QuantizedByteVectorValues get();
+}

libs/simdvec/src/main21/java/org/elasticsearch/simdvec/internal/Int7SQVectorScorerSupplier.java

@@ -14,6 +14,7 @@
 import org.apache.lucene.util.hnsw.UpdateableRandomVectorScorer;
 import org.apache.lucene.util.quantization.QuantizedByteVectorValues;
 import org.apache.lucene.util.quantization.ScalarQuantizedVectorSimilarity;
+import org.elasticsearch.simdvec.QuantizedByteVectorValuesAccess;
 
 import java.io.IOException;
 import java.lang.foreign.MemorySegment;
@@ -23,7 +24,7 @@
 import static org.apache.lucene.index.VectorSimilarityFunction.MAXIMUM_INNER_PRODUCT;
 import static org.apache.lucene.util.quantization.ScalarQuantizedVectorSimilarity.fromVectorSimilarity;
 
-public abstract sealed class Int7SQVectorScorerSupplier implements RandomVectorScorerSupplier {
+public abstract sealed class Int7SQVectorScorerSupplier implements RandomVectorScorerSupplier, QuantizedByteVectorValuesAccess {
 
     static final byte BITS = 7;
 
@@ -107,6 +108,11 @@ public void setScoringOrdinal(int node) throws IOException {
         };
     }
 
+    @Override
+    public QuantizedByteVectorValues get() {
+        return values;
+    }
+
     public static final class EuclideanSupplier extends Int7SQVectorScorerSupplier {
 
         public EuclideanSupplier(MemorySegmentAccessInput input, QuantizedByteVectorValues values, float scoreCorrectionConstant) {