Logging improvement

Is your feature request related to a problem? Please describe.

The current info logs need to be less verbose. We can see DB query statements.
Also, the info logs are not helpful as they do not provide information at the handler level (request success or failure, etc.).

Fixed in #183 — logging migrated to slog with configurable log level, DB query logs reduced to warn level, and structured request/response logging added via connectRPC middleware.