feat(runs): add additionalInstructions property to RunRequest (#293)

Co-authored-by: ahmedharis994 <haris.mirza@10Pearls.com>

openai-core/src/commonMain/kotlin/com.aallam.openai.api/run/RunRequest.kt

@@ -30,6 +30,12 @@ public data class RunRequest(
      */
     @SerialName("instructions") val instructions: String? = null,
 
+    /**
+     * Appends additional instructions at the end of the instructions for the run.
+     * This is useful for modifying the behavior on a per-run basis without overriding other instructions.
+     */
+    @SerialName("additional_instructions") val additionalInstructions: String? = null,
+
     /**
      * Override the tools the assistant can use for this run.
      * This is useful for modifying the behavior on a per-run basis.
@@ -74,6 +80,12 @@ public class RunRequestBuilder {
      */
     public var instructions: String? = null
 
+    /**
+     * Appends additional instructions at the end of the instructions for the run.
+     * This is useful for modifying the behavior on a per-run basis without overriding other instructions.
+     */
+    public var additionalInstructions: String? = null,
+
     /**
      * Override the tools the assistant can use for this run.
      * This is useful for modifying the behavior on a per-run basis.
@@ -94,6 +106,7 @@ public class RunRequestBuilder {
         assistantId = requireNotNull(assistantId) { "assistantId is required" },
         model = model,
         instructions = instructions,
+        additionalInstructions = additionalInstructions,
         tools = tools,
         metadata = metadata,
     )