T21: Use float[] instead of List<Double> in EmbeddingModelTypes

Avoids boxing 1536+ Double objects per embedding. float[] matches
Spring AI's native embedding representation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: donald-pinckney

TASK_QUEUE.json

@@ -78,7 +78,7 @@
       "severity": "low",
       "category": "improvement",
       "depends_on": [],
-      "status": "todo",
+      "status": "completed",
       "notes": "DABH review comment: https://github.com/temporalio/sdk-java/pull/2829/files#r3054058971"
     },
     {

temporal-spring-ai/src/main/java/io/temporal/springai/activity/EmbeddingModelActivityImpl.java

@@ -25,7 +25,7 @@ public EmbeddingModelActivityImpl(EmbeddingModel embeddingModel) {
   @Override
   public EmbeddingModelTypes.EmbedOutput embed(EmbeddingModelTypes.EmbedTextInput input) {
     float[] embedding = embeddingModel.embed(input.text());
-    return new EmbeddingModelTypes.EmbedOutput(toDoubleList(embedding));
+    return new EmbeddingModelTypes.EmbedOutput(embedding);
   }
 
   @Override
@@ -38,8 +38,7 @@ public EmbeddingModelTypes.EmbedBatchOutput embedBatch(
             .mapToObj(
                 i -> {
                   var embedding = response.getResults().get(i);
-                  return new EmbeddingModelTypes.EmbeddingResult(
-                      i, toDoubleList(embedding.getOutput()));
+                  return new EmbeddingModelTypes.EmbeddingResult(i, embedding.getOutput());
                 })
             .collect(Collectors.toList());
 
@@ -62,11 +61,4 @@ public EmbeddingModelTypes.EmbedBatchOutput embedBatch(
   public EmbeddingModelTypes.DimensionsOutput dimensions() {
     return new EmbeddingModelTypes.DimensionsOutput(embeddingModel.dimensions());
   }
-
-  private List<Double> toDoubleList(float[] floats) {
-    return IntStream.range(0, floats.length)
-        .mapToDouble(i -> floats[i])
-        .boxed()
-        .collect(Collectors.toList());
-  }
 }

temporal-spring-ai/src/main/java/io/temporal/springai/model/EmbeddingModelTypes.java

@@ -31,7 +31,7 @@ public record EmbedBatchInput(List<String> texts) {}
    *
    * @param embedding the embedding vector
    */
-  public record EmbedOutput(List<Double> embedding) {}
+  public record EmbedOutput(float[] embedding) {}
 
   /**
    * Output containing multiple embedding vectors.
@@ -47,7 +47,7 @@ public record EmbedBatchOutput(List<EmbeddingResult> embeddings, EmbeddingMetada
    * @param index the index in the original input list
    * @param embedding the embedding vector
    */
-  public record EmbeddingResult(int index, List<Double> embedding) {}
+  public record EmbeddingResult(int index, float[] embedding) {}
 
   /**
    * Metadata about the embedding operation.