Export COMMENT instead EMPTY runtime helper

Editor assessment

The header `fix(compiler): export COMMENT instead EMPTY runtime helper` states the changed behavior directly, so a reader grasps what was fixed and where without consulting the diff. The `fix` type is accurate and the scope `compiler` correctly identifies the affected area. No body or footer is required for a change of this size. Style is clean: imperative mood, no trailing period, and a subject well within a sensible length. A body explaining the underlying cause would make this fully instructive, but for a contained change the omission is acceptable, leaving a clear, correct, publishable message.