v1.18.47

Patch release republishing the verified v1.18.46 hardening commit to refresh downstream package indexing.\n\nIncludes the latest verified fixes for bounded parallel tool IPC payload handling and compacted HITL Read receipt regressions.\n\nValidation before tag:\n- composer validate --strict\n- composer audit --format=plain\n- composer run lint\n- composer test (2696 tests, 6623 assertions, 2 skipped)