Add structured logging, correlation IDs, and metrics endpoint

[dangerworm]

Summary

• configure JSON console logging with correlation IDs and request logging middleware
• add shared metrics collector that tracks requests, database operations, and external calls with a /metrics endpoint
• instrument database services and API callers with contextual logging and document observability usage

Testing

• dotnet build api/TornTools.sln (fails: dotnet CLI not available in environment)

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Codex Task