fix(clean): preserve Gradle DSL cache integrity

Preserve Gradle DSL hash cache integrity by normalizing file-level cleanup targets to the containing hash directory.

Verification:
- ./scripts/check.sh --format
- MOLE_TEST_NO_AUTH=1 bats tests/regression.bats tests/clean_dev_caches.bats
- MOLE_TEST_NO_AUTH=1 MOLE_TEST_JOBS=2 BATS_FORMATTER=tap ./scripts/test.sh