add license

Author: Sunrisea

spring-ai-alibaba-observation-extension/src/main/java/com/alibaba/cloud/ai/observation/client/prompt/PromptMetadataAwareChatClientObservationConvention.java

@@ -1,3 +1,20 @@
+/*
+ * Copyright 2024-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
 package com.alibaba.cloud.ai.observation.client.prompt;
 
 import static com.alibaba.cloud.ai.observation.constants.MetadataAttributes.AGENT_IP;