Align CI workflows with stripzip

[Code0x58]

Summary

• replace the ad-hoc CI workflow with the one used in python-stripzip so coverage and test results are reported via Codecov
• update the publish workflow to match python-stripzip’s trusted publishing setup

Testing

• pytest -q

---

Codex Task

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.83%. Comparing base (2196c8e) to head (1a7b82e).
⚠️ Report is 6 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master       #9      +/-   ##
==========================================
- Coverage   98.62%   95.83%   -2.79%     
==========================================
  Files           1        1              
  Lines         145      144       -1     
==========================================
- Hits          143      138       -5     
- Misses          2        6       +4     

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