Add configurable request and response logging

[jbeckwith-oai]

Carried over from #126 and originally requested by @akshah123.

The client currently has no supported way to inject a logger such as Rails.logger and observe outgoing requests and incoming responses. A logger integration would help applications debug API behavior and correlate SDK traffic with their own logs.

Desired behavior

• Accept a standard Ruby logger-compatible object at client construction (including Rails.logger).
• Log useful request and response metadata with configurable verbosity.
• Redact authorization credentials and other sensitive headers by default.
• Make body/payload logging explicit and safe, especially for file uploads and streaming responses.
• Include request IDs, status, timing, and retry information where available.
• Document the feature and add tests for redaction and streaming behavior.

Related: #242 tracks a narrower request for retry callbacks/visibility. Source: #126.