feat: add Prometheus metrics endpoint - #224

Process completed with exit code 1.

'NativeAsset' is assigned a value but never used

'reprServer' is defined but never used

'scvToXDR' is defined but never used

'mappedNgos' is assigned a value but never used

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-node@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/