fix(runner): run teardown after setup failure

[Chemaclass]

Background

Closes #1318

A failing set_up_before_script skips all tests but previously also skipped tear_down_after_script. Resources acquired before a later setup command failed were left behind.

Changes

• Run tear_down_after_script before clearing file hooks and script-scoped temporary state when setup fails
• Apply the same lifecycle to benchmark files
• Cover cleanup with an actual resource marker in sequential, parallel, and benchmark runs
• Document partial initialization and defensive teardown

Verification

• ./bashunit -s -p --skip-env-file tests/acceptance/bashunit_setup_before_script_error_test.sh tests/acceptance/bashunit_bench_test.sh (12 tests, 46 assertions)
• make sa
• make lint
• make docs/build
• git diff --check

Checklist

• I updated the CHANGELOG.md to reflect the fix
• I updated the documentation to reflect the changes