Add mock DOM layer to run_tests.ml so hyperscript behavioral tests
(spec/tests/test-hyperscript-behavioral.sx) can run in the OCaml test
runner without a browser. Previously these tests required Playwright
which crashed after 10 minutes from WASM page reboots.
Mock DOM implementation:
- host-global, host-get, host-set!, host-call, host-new, host-callback,
host-typeof, host-await — OCaml primitives operating on SX Dict elements
- Mock elements with classList, style, attributes, event dispatch + bubbling
- querySelector/querySelectorAll with #id, .class, tag, [attr] selectors
- Load web/lib/dom.sx and web/lib/browser.sx for dom-* wrappers
- eval-hs function for expression-only tests (comparisonOperator, etc.)
Result: 367/831 HS tests pass in ~30 seconds (was: Playwright crash).
14 suites at 100%: live, component, liveTemplate, scroll, call, go,
focus, log, reactive-properties, resize, measure, attributeRef,
objectLiteral, queryRef.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>