DVO-1024: log "id" claim from CL authorization token

[ilyaluk]

📝 Summary

Engine API auth includes optional "id" claim which CL might set to its, well, id. This change adds logging not only remote IP of the CL node, but also its "id", if set.

⛱ Motivation and Context

It's hard to debug issues if only IP is seen in logs, and you need to map back from IP to exact CL node this IP refers to. If CL node sets its id in tokens, log it. This improves troubleshooting.

📚 References

https://github.com/ethereum/execution-apis/blob/main/src/engine/authentication.md#jwt-claims

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✅ I have run these commands

• make lint
• make test-race
• go mod tidy
• I have seen and agree to CONTRIBUTING.md

[Copilot]

Pull Request Overview

This PR logs the "id" claim from a CL authorization token to enhance traceability when debugging Engine API authentication issues.

• Extracts and logs the optional "id" claim from JWT tokens in proxy.go.
• Updates function signatures to pass a logger for enhanced logging context.
• Migrates the JWT dependency to v5 and updates token generation accordingly.

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 1 comment.

File	Description
proxy.go	Adds functions to extract the "id" claim and updates logging usage.
go.mod	Updates the JWT dependency to "github.com/golang-jwt/jwt/v5".
cmd/jwt-tokens-service/main.go	Updates JWT token generation to match the new dependency.

Comments suppressed due to low confidence (1)

cmd/jwt-tokens-service/main.go:68

• [nitpick] Confirm that using time.Now() instead of jwt.TimeFunc() for the 'iat' claim is intentional, as it might affect test scenarios that rely on the overridable time function.

	claims["iat"] = time.Now().Unix()