ref(kafka): Reimplement SentryKafkaProducer as a dynamic Proxy

Replace the concrete `implements Producer<K,V>` class with a
`Proxy.newProxyInstance`-based wrapper that intercepts only the two
`send()` overloads and forwards every other method reflectively to
the delegate.

The concrete class required explicitly delegating every method on the
`Producer` interface, coupling the wrapper to a specific Kafka version:
`clientInstanceId(Duration)` was added in Kafka 3.7, and the deprecated
`sendOffsetsToTransaction(Map, String)` was removed in Kafka 4.0. The
dynamic proxy has no such coupling — new or removed interface methods are
handled automatically, giving full compatibility across all Kafka
client versions.

Public API change: `SentryKafkaProducer` is now a utility class with
static `wrap()` overloads instead of constructors. Callers wrap a
producer with `SentryKafkaProducer.wrap(producer)`. The Spring BPP and
console sample are updated accordingly.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adinauer

sentry-kafka/api/sentry-kafka.api

@@ -9,27 +9,11 @@ public final class io/sentry/kafka/SentryKafkaConsumerTracing {
 	public static fun withTracing (Lorg/apache/kafka/clients/consumer/ConsumerRecord;Ljava/util/concurrent/Callable;)Ljava/lang/Object;
 }
 
-public final class io/sentry/kafka/SentryKafkaProducer : org/apache/kafka/clients/producer/Producer {
+public final class io/sentry/kafka/SentryKafkaProducer {
 	public static final field SENTRY_ENQUEUED_TIME_HEADER Ljava/lang/String;
 	public static final field TRACE_ORIGIN Ljava/lang/String;
-	public fun <init> (Lorg/apache/kafka/clients/producer/Producer;)V
-	public fun <init> (Lorg/apache/kafka/clients/producer/Producer;Lio/sentry/IScopes;)V
-	public fun <init> (Lorg/apache/kafka/clients/producer/Producer;Lio/sentry/IScopes;Ljava/lang/String;)V
-	public fun abortTransaction ()V
-	public fun beginTransaction ()V
-	public fun clientInstanceId (Ljava/time/Duration;)Lorg/apache/kafka/common/Uuid;
-	public fun close ()V
-	public fun close (Ljava/time/Duration;)V
-	public fun commitTransaction ()V
-	public fun flush ()V
-	public fun getDelegate ()Lorg/apache/kafka/clients/producer/Producer;
-	public fun initTransactions ()V
-	public fun metrics ()Ljava/util/Map;
-	public fun partitionsFor (Ljava/lang/String;)Ljava/util/List;
-	public fun send (Lorg/apache/kafka/clients/producer/ProducerRecord;)Ljava/util/concurrent/Future;
-	public fun send (Lorg/apache/kafka/clients/producer/ProducerRecord;Lorg/apache/kafka/clients/producer/Callback;)Ljava/util/concurrent/Future;
-	public fun sendOffsetsToTransaction (Ljava/util/Map;Ljava/lang/String;)V
-	public fun sendOffsetsToTransaction (Ljava/util/Map;Lorg/apache/kafka/clients/consumer/ConsumerGroupMetadata;)V
-	public fun toString ()Ljava/lang/String;
+	public static fun wrap (Lorg/apache/kafka/clients/producer/Producer;)Lorg/apache/kafka/clients/producer/Producer;
+	public static fun wrap (Lorg/apache/kafka/clients/producer/Producer;Lio/sentry/IScopes;)Lorg/apache/kafka/clients/producer/Producer;
+	public static fun wrap (Lorg/apache/kafka/clients/producer/Producer;Lio/sentry/IScopes;Ljava/lang/String;)Lorg/apache/kafka/clients/producer/Producer;
 }