Add workload id as metric to builder

[avalonche]

📝 Summary

Adds workload ID computation and metrics to the builder for TEE workload
identification. The workload ID uniquely identifies a TEE workload based on its measurement registers
and is now exposed as a Prometheus metric for monitoring and observability.

Key changes:

• Implements compute_workload_id function that parses Automata's serialized verifier output and computes
  a unique workload identifier
• Exposes workload ID as a Prometheus gauge metric with the workload ID as a label

💡 Motivation and Context

When running the builder in a TEE, it's important to be able to identify and monitor which specific
workload/measurement is running

By exposing this as a metric, operators can:

• Verify the correct TEE workload is running to the one approved and registered unchain
• Monitor and alert on workload changes
• Ensure consistency across builder instances

The implementation follows the
https://github.com/flashbots/flashtestations/tree/7cc7f68492fe672a823dd2dead649793aac1f216 and same workload id from solidity and rust verified.

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✅ I have completed the following steps:

• Run make lint
• Run make test
• Added tests (if applicable)