feat: add BullMQ integration

[jrothrock]

Summary

Adds Scout APM instrumentation for BullMQ Worker job processing via a require-time shim on Worker.prototype.callProcessJob.

What's instrumented

Each job processed by a BullMQ Worker is wrapped in a Scout transaction + span with the operation name Job/{jobName}. The following context is attached to every span:

Context key	Value
queue	BullMQ queue name
task_id	BullMQ job ID
priority	Job priority (or "unknown" if unset)
scout.job_queue_time_ns	Time from job enqueue to processing start (nanoseconds)
error	"true" if the processor throws

Implementation approach

The shim patches Worker.prototype.callProcessJob (BullMQ's internal method that dispatches a single job to the user-provided processor). This is the narrowest possible hook point — it fires once per job execution regardless of concurrency settings, and it's the right place to measure end-to-end job duration including any internal BullMQ overhead before the processor runs.

Changes

• lib/integrations/bullmq.ts — new BullMQIntegration class
• lib/integrations/index.ts — registers bullmq in KNOWN_PACKAGES and getIntegrationForPackage
• lib/types/enum.ts — adds ScoutContextName.TaskId, ScoutContextName.Priority, and ScoutSpanOperation.BullMQJob
• test/integrations/bullmq.e2e.ts — e2e tests covering span creation, queue/task_id/priority/queue_time context, and error flag

Test plan

• Job/{name} span is created for each processed job
• queue, task_id, priority, and scout.job_queue_time_ns context values are present and correct
• error: "true" is set on the span when the processor throws
• Integration is a no-op when Scout monitor is disabled (scout not set)
• Manual verification: run node_test_apps bullmq demo app and confirm Job/ spans appear in Scout APM UI

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