feat(CuckooFilter): add cf.info and cf.count command

[ChaseForward]

part of: #3552

Summary

Add RedisBloom-compatible CF.INFO and CF.COUNT support for Cuckoo Filter.

Design

CF.INFO returns the filter metadata (total slot size, number of buckets,
number of sub-filters, number of items inserted/deleted, bucket size,
expansion rate, max iterations), matching RedisBloom's field order.

CF.INFO key items returns a nested key-value pair for inserted and deleted
counts; CF.INFO key returns all fields as a flat array.

CF.COUNT returns the total number of fingerprint matches across all
sub-filters for the given item, counting each occurrence separately
(duplicates inserted via CF.ADD are all counted), without modifying any
slot.

This PR was written using TRAE.

[github-actions]

Hi @ChaseForward,

Thank you for your pull request. Please review our Contributing Guide.

Please make sure you understand your changes and explain your reasoning in this pull request. Low-quality pull requests may be closed.

[jihuayu]

Hi @ChaseForward Thank you for your contribution. Unless there is a necessary reason to do otherwise, please limit each PR to adding a single command.

I’m going to close this PR. You can split it into two separate PRs and resubmit them.