v0.2.0 of loq_shelf

Structured request logging middleware for Shelf, powered by loq. Drop-in replacement for logRequests() with structured fields, zone context, and configurable log levels. Changelog excerpt: ### Breaking - **Sealed event hierarchy.**Hooks now receive a typed ShelfLogEventinstead of raw Request/ Response/ Durationpositional arguments. Three concrete variants live under the sealed base: - ShelfRequestStartEventfor the start log. Carries requestand defaults; elapsedis null. - ShelfResponseEventfor the completion log. Carries request, response, elapsed, defaults. - ShelfRequestErrorEventfor the error log. Carries request, elapsed, defaults. [...]