docs: document new logs and prometheus metrics

[cdr-robot]

Original Issue

From coder/coder#17488

Documentation needed for new logs and prometheus metrics that were added in previous pull requests.

Assignment

@coder

[github-actions]

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[cdr-robot]

I've created PR #35 to address this issue with documentation updates for the new logs and Prometheus metrics.

The PR includes:

• Documentation for enhanced request logs with auth context and DB info
• Documentation for the new labels added to API metrics
• Information about deprecated metrics
• Added monitoring best practices and example Prometheus queries

There seems to be an issue with the CI checks, possibly related to repository permissions. The changes are ready for review, and I can make any additional updates as needed.