Add OpenTelemetry v2 plugin

contrib/temporal-opentelemetry-v2/build.gradle

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+description = '''Temporal Java SDK OpenTelemetry v2 Module'''
+
+ext {
+    otelVersion = '1.66.0'
+}
+
+dependencies {
+    api platform("io.opentelemetry:opentelemetry-bom:$otelVersion")
+
+    compileOnly project(':temporal-serviceclient')
+    compileOnly project(':temporal-sdk')
+    compileOnly "javax.annotation:javax.annotation-api:$annotationApiVersion"
+
+    implementation "com.google.guava:guava:$guavaVersion"
+
+    api "io.opentelemetry:opentelemetry-api"
+    api "io.opentelemetry:opentelemetry-sdk-trace"
+    api "io.opentelemetry:opentelemetry-sdk-metrics"
+    api "io.opentelemetry:opentelemetry-sdk-logs"
+
+    testImplementation project(':temporal-sdk')
+    testImplementation project(':temporal-serviceclient')
+    testImplementation project(':temporal-testing')
+    testImplementation "io.opentelemetry:opentelemetry-sdk-testing"
+    testImplementation "junit:junit:${junitVersion}"
+
+    testRuntimeOnly group: 'ch.qos.logback', name: 'logback-classic', version: "${logbackVersion}"
+}

contrib/temporal-opentelemetry-v2/src/main/java/io/temporal/opentelemetry/v2/OpenTelemetryActivityClientInterceptor.java

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+package io.temporal.opentelemetry.v2;
+
+import io.temporal.common.interceptors.ActivityClientCallsInterceptor;
+import io.temporal.common.interceptors.ActivityClientInterceptorBase;
+import io.temporal.opentelemetry.v2.internal.InterceptorTracer;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryActivityClientCallsInterceptor;
+
+public class OpenTelemetryActivityClientInterceptor extends ActivityClientInterceptorBase {
+  private final InterceptorTracer tracer;
+
+  public OpenTelemetryActivityClientInterceptor(InterceptorTracer tracer) {
+    this.tracer = tracer;
+  }
+
+  @Override
+  public ActivityClientCallsInterceptor activityClientCallsInterceptor(
+      ActivityClientCallsInterceptor next) {
+    return new OpenTelemetryActivityClientCallsInterceptor(tracer, next);
+  }
+}

contrib/temporal-opentelemetry-v2/src/main/java/io/temporal/opentelemetry/v2/OpenTelemetryClientInterceptor.java

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+package io.temporal.opentelemetry.v2;
+
+import io.temporal.common.interceptors.WorkflowClientCallsInterceptor;
+import io.temporal.common.interceptors.WorkflowClientInterceptorBase;
+import io.temporal.opentelemetry.v2.internal.InterceptorTracer;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryWorkflowClientCallsInterceptor;
+
+public class OpenTelemetryClientInterceptor extends WorkflowClientInterceptorBase {
+  private final InterceptorTracer tracer;
+
+  public OpenTelemetryClientInterceptor(InterceptorTracer tracer) {
+    this.tracer = tracer;
+  }
+
+  @Override
+  public WorkflowClientCallsInterceptor workflowClientCallsInterceptor(
+      WorkflowClientCallsInterceptor next) {
+    return new OpenTelemetryWorkflowClientCallsInterceptor(tracer, next);
+  }
+}

contrib/temporal-opentelemetry-v2/src/main/java/io/temporal/opentelemetry/v2/OpenTelemetryNexusClientInterceptor.java

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+package io.temporal.opentelemetry.v2;
+
+import io.temporal.common.interceptors.NexusClientCallsInterceptor;
+import io.temporal.common.interceptors.NexusClientInterceptorBase;
+import io.temporal.opentelemetry.v2.internal.InterceptorTracer;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryNexusClientCallsInterceptor;
+
+public class OpenTelemetryNexusClientInterceptor extends NexusClientInterceptorBase {
+  private final InterceptorTracer tracer;
+
+  public OpenTelemetryNexusClientInterceptor(InterceptorTracer tracer) {
+    this.tracer = tracer;
+  }
+
+  @Override
+  public NexusClientCallsInterceptor nexusClientCallsInterceptor(NexusClientCallsInterceptor next) {
+    return new OpenTelemetryNexusClientCallsInterceptor(tracer, next);
+  }
+}

contrib/temporal-opentelemetry-v2/src/main/java/io/temporal/opentelemetry/v2/OpenTelemetryPlugin.java

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+package io.temporal.opentelemetry.v2;
+
+import io.temporal.common.Experimental;
+import io.temporal.common.SimplePlugin;
+import io.temporal.opentelemetry.v2.internal.InterceptorTracer;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryContextPropagator;
+
+/**
+ * OpenTelemetry v2 plugin for Temporal clients and workers.
+ *
+ * <p>Set it on {@code WorkflowServiceStubsOptions}, {@code WorkflowClientOptions}, or {@code
+ * WorkerFactoryOptions}. The SDK propagates plugins down that chain.
+ *
+ * <p>Register a {@link ReplaySafeOpenTelemetry} with {@code GlobalOpenTelemetry.set} before calling
+ * {@link Builder#build()}.
+ */
+@Experimental
+public final class OpenTelemetryPlugin extends SimplePlugin {
+  public static final String NAME = "io.temporal.opentelemetry.v2";
+
+  private OpenTelemetryPlugin(InterceptorTracer tracer) {
+    super(
+        SimplePlugin.newBuilder(NAME)
+            .addClientInterceptors(new OpenTelemetryClientInterceptor(tracer))
+            .addScheduleClientInterceptors(new OpenTelemetryScheduleClientInterceptor(tracer))
+            .addActivityClientInterceptors(new OpenTelemetryActivityClientInterceptor(tracer))
+            .addNexusClientInterceptors(new OpenTelemetryNexusClientInterceptor(tracer))
+            .addWorkerInterceptors(new OpenTelemetryWorkerInterceptor(tracer))
+            .addContextPropagators(new OpenTelemetryContextPropagator()));
+  }
+
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  /** Every option is optional; an unset one keeps its default. */
+  public static final class Builder {
+    private String headerKey = "_tracer-data";
+    private boolean addTemporalSpans;
+
+    private Builder() {}
+
+    /**
+     * The Temporal header key to serialize the span to. Defaults to {@code _tracer-data}, which
+     * Temporal uses; overriding it breaks trace continuity with workers using the standard key.
+     */
+    public Builder setHeaderKey(String headerKey) {
+      this.headerKey = headerKey;
+      return this;
+    }
+
+    /**
+     * Whether to create spans for Temporal operations such as StartWorkflow, RunWorkflow, and
+     * RunActivity. Defaults to false: trace context still propagates through Temporal headers, so
+     * spans created by application code remain connected.
+     */
+    public Builder setAddTemporalSpans(boolean addTemporalSpans) {
+      this.addTemporalSpans = addTemporalSpans;
+      return this;
+    }
+
+    public OpenTelemetryPlugin build() {
+      if (!ReplaySafeOpenTelemetry.isRegisteredGlobally()) {
+        throw new IllegalStateException(
+            "the global OpenTelemetry must be a ReplaySafeOpenTelemetry; build one with "
+                + "ReplaySafeOpenTelemetry.newBuilder() and register it with "
+                + "GlobalOpenTelemetry.set before building this plugin");
+      }
+      return new OpenTelemetryPlugin(new InterceptorTracer(headerKey, addTemporalSpans));
+    }
+  }
+}

contrib/temporal-opentelemetry-v2/src/main/java/io/temporal/opentelemetry/v2/OpenTelemetryScheduleClientInterceptor.java

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+package io.temporal.opentelemetry.v2;
+
+import io.temporal.common.interceptors.ScheduleClientCallsInterceptor;
+import io.temporal.common.interceptors.ScheduleClientInterceptorBase;
+import io.temporal.opentelemetry.v2.internal.InterceptorTracer;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryScheduleClientCallsInterceptor;
+
+public class OpenTelemetryScheduleClientInterceptor extends ScheduleClientInterceptorBase {
+  private final InterceptorTracer tracer;
+
+  public OpenTelemetryScheduleClientInterceptor(InterceptorTracer tracer) {
+    this.tracer = tracer;
+  }
+
+  @Override
+  public ScheduleClientCallsInterceptor scheduleClientCallsInterceptor(
+      ScheduleClientCallsInterceptor next) {
+    return new OpenTelemetryScheduleClientCallsInterceptor(tracer, next);
+  }
+}

contrib/temporal-opentelemetry-v2/src/main/java/io/temporal/opentelemetry/v2/OpenTelemetryWorkerInterceptor.java

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+package io.temporal.opentelemetry.v2;
+
+import io.nexusrpc.handler.OperationContext;
+import io.temporal.common.interceptors.ActivityInboundCallsInterceptor;
+import io.temporal.common.interceptors.NexusOperationInboundCallsInterceptor;
+import io.temporal.common.interceptors.WorkerInterceptor;
+import io.temporal.common.interceptors.WorkflowInboundCallsInterceptor;
+import io.temporal.opentelemetry.v2.internal.InterceptorTracer;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryActivityInboundCallsInterceptor;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryNexusOperationInboundCallsInterceptor;
+import io.temporal.opentelemetry.v2.internal.OpenTelemetryWorkflowInboundCallsInterceptor;
+
+public class OpenTelemetryWorkerInterceptor implements WorkerInterceptor {
+  private final InterceptorTracer tracer;
+
+  public OpenTelemetryWorkerInterceptor(InterceptorTracer tracer) {
+    this.tracer = tracer;
+  }
+
+  @Override
+  public WorkflowInboundCallsInterceptor interceptWorkflow(WorkflowInboundCallsInterceptor next) {
+    return new OpenTelemetryWorkflowInboundCallsInterceptor(tracer, next);
+  }
+
+  @Override
+  public ActivityInboundCallsInterceptor interceptActivity(ActivityInboundCallsInterceptor next) {
+    return new OpenTelemetryActivityInboundCallsInterceptor(tracer, next);
+  }
+
+  @Override
+  public NexusOperationInboundCallsInterceptor interceptNexusOperation(
+      OperationContext context, NexusOperationInboundCallsInterceptor next) {
+    return new OpenTelemetryNexusOperationInboundCallsInterceptor(tracer, next);
+  }
+}