Parser now handles 'does not start with' and 'does not end with'
comparison operators, compiling to (not (starts-with? ...)) and
(not (ends-with? ...)) respectively.
Test runner: host-set!/host-get stringify innerHTML/textContent.
437/831 (52.6%) — parser fix doesn't change count yet (comparison tests
use 'is a' type checks which need separate fix).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>