SD-11577: augment worker metrics

[rtalvarez]

Pull Request Template

Description

I will probably split this up in multiple PRs, I'm just testing to make sure these 4 things work

Add 4 new Cloudflare metric groups to the Prometheus exporter:

• Worker Wall Time — cloudflare_worker_wall_time gauge with P50/P75/P99/P999 quantiles, extending the existing worker invocations flow.

• KV Operations — cloudflare_kv_requests_count counter and cloudflare_kv_latency gauge from the kvOperationsAdaptiveGroups GraphQL dataset, grouped by namespace ID and action type.

• Worker Subrequests — cloudflare_worker_subrequests_count counter and cloudflare_worker_subrequest_time gauge from the workersSubrequestsAdaptiveGroups GraphQL dataset, grouped by script name.

• Queue Metrics — cloudflare_queue_backlog_messages, cloudflare_queue_backlog_bytes, and cloudflare_queue_consumer_concurrency gauges from the queueBacklogAdaptiveGroups and queueConsumerMetricsAdaptiveGroups GraphQL datasets. Queue IDs are resolved to human-readable names via the Queues REST API, falling back to the raw ID if not found.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring
• Other (please describe):

Testing

• I have run make pr-tests and all tests pass
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Code Quality

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation

Before Submitting

Please ensure you have completed the following before submitting your PR:

# Run comprehensive tests
make pr-tests

If the above command fails, please fix the issues before submitting your PR.

Additional Notes

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