The committed PHPUnit runner lived at tools/.bin/phpunit.phar, away from
the suite it runs. Move it next to the tests it drives —
tests/phpunit.phar — and update every invocation to
`php tests/phpunit.phar -c tests/phpunit.xml.dist`:
- CI workflows (ci, build-release, build_pre-release) + the ci.yml header,
- CLAUDE.md, CONTRIBUTING.md, tools/README.md, the qa-lead-reviewer agent,
- docs/en (dev-workflow, updates_checklist, phpunit-phar, refactoring).
docs/ru is generated from docs/en (make docs-translate) and is left for
the next regeneration, per the docs workflow.
