Opamp always on profiler locks reporting

[robsunday]

This PR adds thread lock state reporting for JFR thread-dump samples. When enabled, profiling samples include lock relationships alongside thread stack and state information, improving visibility into blocked threads and deadlocks.

Changes

• Added report_locks declarative configuration.

• Added splunk.profiler.locks.enabled environment configuration.

• Extended thread-dump parsing to capture:

  • Locks a thread is waiting on
  • The owning thread
  • Locks held by the thread

• Added support for extracting lock owners from JFR deadlock reports.

• Added lock labels to exported pprof samples:

  • lock.waiting_on
  • lock.owner_thread
  • lock.held.

• Preserved lock metadata even when stack traces are truncated by the configured stack depth.

• Refactored thread-dump parsing into the threaddump package and introduced structured stack trace data.

• Added parser, processor, deadlock extraction, configuration, and exporter tests, including deadlock and blocked-thread fixtures.

Lock reporting remains disabled by default.

Limitations

Ownable synchronizer owners, such as ReentrantLock holders, can only be resolved when the JFR thread dump includes matching deadlock information.