[kafka] Consolidate DSM mentions into a single top-of-page callout

Switches the top callout to the same purple "NEW Kafka Monitoring" box
treatment used in the sibling docs PR, with Piotr's wording (consumer
lag, throughput, schemas, message reading).

Removes two redundant mid-page "Add Data Streams Monitoring..." lines
that duplicated the top callout. Cleans up the now-orphan [24] and
[25] reference definitions.

Per @piochelepiotr's PR comment.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: johannbotha

kafka/README.md

@@ -2,14 +2,17 @@
 
 ![Kafka Dashboard][1]
 
-**Already collecting Kafka metrics with the Agent?** Pair them with [Data Streams Monitoring for Kafka][26] to track end-to-end producer/consumer lag, throughput, and message lineage.
+<div style="background:#f3edfa;border-left:4px solid #632ca6;padding:14px 18px;margin:24px 0;border-radius:4px;">
+  <p style="margin:0;line-height:1.5;">
+    <span style="display:inline-block;background:#632ca6;color:#fff;font-size:10px;font-weight:700;padding:2px 8px;border-radius:4px;letter-spacing:0.06em;text-transform:uppercase;margin-right:8px;vertical-align:middle;">New</span>
+    <strong>Kafka Monitoring</strong> tracks consumer lag, throughput, schemas, and adds message reading capabilities. <a href="https://docs.datadoghq.com/data_streams/kafka?utm_source=docs&utm_medium=callout&utm_campaign=DocsCTA-DSMKafka-IntegrationsKafka">Try Kafka Monitoring &rarr;</a>
+  </p>
+</div>
 
 ## Overview
 
 View Kafka broker metrics and logs for a 360-view of the health and performance of your Kafka clusters in real time.
 
-Add [Data Streams Monitoring][24] to your producers and consumers to visualize the application topology, root cause issues across services, and measure end to end latency, throughput and lag.
-
 **Note**:
 
 - This check has a limit of 350 metrics per instance. The number of returned metrics is indicated in the Agent status output. Specify the metrics you are interested in by editing the configuration below. For more detailed instructions on customizing the metrics to collect, see the
@@ -27,8 +30,6 @@ To collect Kafka consumer metrics, see the [kafka_consumer check][3].
 
 The Agent's Kafka check is included in the [Datadog Agent][4] package, no additional installation is needed on your Kafka nodes.
 
-Add [Data Streams Monitoring][24] to your producers and consumers to visualize the application topology, root cause issues across services, and measure end to end latency, throughput and lag.
-
 The check collects metrics from JMX with [JMXFetch][5]. A JVM is needed on each kafka node so the Agent can run JMXFetch. The same JVM that Kafka uses can be used for this.
 
 **Note**: The Kafka check cannot be used with Managed Streaming for Apache Kafka (Amazon MSK). Use the [Amazon MSK integration][6] instead.
@@ -186,6 +187,3 @@ See [service_checks.json][15] for a list of service checks provided by this inte
 [21]: https://www.datadoghq.com/blog/monitor-kafka-with-datadog
 [22]: https://raw.githubusercontent.com/DataDog/dd-agent/5.2.1/conf.d/kafka.yaml.example
 [23]: https://www.datadoghq.com/knowledge-center/apache-kafka/
-[24]: https://docs.datadoghq.com/data_streams/
-[25]: /data-streams
-[26]: https://docs.datadoghq.com/data_streams/kafka?utm_source=docs&utm_medium=callout&utm_campaign=DocsCTA-DSMKafka-IntegrationsKafka