refactor(core): drop unused run_silent/run_logged wrappers

Both helpers in lib/core/log.sh had zero callers across mole/install.sh/lib/bin/scripts/tests.
run_silent was a one-line ': $@ >/dev/null 2>&1 || true' shim; run_logged was a 14-line
MO_DEBUG branch wrapper. Removing both with no functional impact.