Returns information about the current state of the policy cache in Redis.

This endpoint provides:
• Cache availability status (true if Redis is configured)
• Number of policies currently cached in Redis
• Cache TTL configuration (seconds)

The cacheSize, hitRate, policiesByType and status members are declared by the
schema but are not populated on this route, so they are emitted at their zero/null
values; totalPolicies is a per-tenant figure and reads 0 on the global route.

Use Cases:
• Monitor cache health and efficiency
• Troubleshoot policy synchronization issues
• Verify cache configuration
• Performance analysis and optimization

Optionally specify a tenant ID to check cache status for a specific tenant.