Add configurable cache hit/miss logging with HTTP request correlation

## Request

Add well-defined, configurable logging for cache hits and misses. Each log entry should include a reference to the HTTP request that triggered the cache lookup, enabling operators to correlate cache behavior with specific request patterns.

## Scope

- Cache hit: log key, latency, triggering request info (method, path, request ID)
- Cache miss: log key, triggering request info, reason (cold, expired, evicted)
- Logging should be individually configurable (e.g., per-table, per-cache-type, or via log level)
- Should not add overhead when cache logging is disabled

## Use case

Debugging cache efficiency and diagnosing latency issues requires knowing what's hitting/missing the cache and what requests are driving that behavior.

🤖 Filed by Claude on behalf of Kris.