Remove phpdbg from coverage target

[ohmyfelix]

Summary

• replace -p phpdbg with -p php in the coverage target of Makefile
• align this repository with the org-wide coverage migration tracked in Remove phpdbg from coverage targets and use php instead contributte#73

Motivation

• phpdbg is being removed from coverage targets across Contributte so coverage runs use plain php

Changes

• update both CI and local coverage commands in Makefile

Testing

• make coverage starts the updated php command
• Coverage completes locally (php in this environment has no Xdebug/PCOV, and PHPDBG is intentionally no longer used)
• CI passes

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.92%. Comparing base (b90e7fd) to head (bcaf85a).
⚠️ Report is 8 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #30      +/-   ##
==========================================
- Coverage   78.04%   76.92%   -1.13%     
==========================================
  Files           2        3       +1     
  Lines         123      117       -6     
==========================================
- Hits           96       90       -6     
  Misses         27       27              

☔ 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.