chore: entry count statistics for cache

[cheb0]

Description

allow to see how many blocks are in the cache right now on dashboards

---

• I have read and followed all requirements in CONTRIBUTING.md;
• I used LLM/AI assistance to make this pull request;

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.56%. Comparing base (03b2cad) to head (553ff60).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #428      +/-   ##
==========================================
- Coverage   70.62%   70.56%   -0.07%     
==========================================
  Files         219      219              
  Lines       16970    17020      +50     
==========================================
+ Hits        11985    12010      +25     
- Misses       4089     4107      +18     
- Partials      896      903       +7     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.