🔭 feat(o11y): Add Prometheus Metrics Endpoint and HTTP Instrumentation

[pjhampton]

Summary

Adds prometheus metrics endpoint

Change Type

• New feature (non-breaking change which adds functionality)

Testing

Start - visit /metrics

1. curl http://localhost:3000/metrics returned default process metrics (CPU, memory, event loop lag, etc.)
2. Made requests to / and /login, then re-curled /metrics -- confirmed both admin_http_requests_total and admin_http_request_duration_seconds appeared with correct labels:

admin_http_requests_total{method="GET",path="/",status_code="200"} 1
admin_http_requests_total{method="GET",path="/login",status_code="307"} 1
admin_http_request_duration_seconds_sum{method="GET",path="/",status_code="200"} 0.162622
admin_http_request_duration_seconds_sum{method="GET",path="/login",status_code="307"} 0.000762375

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• I have made pertinent documentation changes
• My changes do not introduce new warnings
• I have written tests demonstrating that my changes are effective or that my feature works
• Local unit tests pass with my changes
• A pull request for updating the documentation has been submitted.

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ teresama
❌ pjhampton
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