HS: extend parser/runtime + new node test runner; ignore test-results/

- Parser: `--` line comments, `|` op, `result` → `the-result`, query-scoped
  `<sel> in <expr>`, `is a/an <type>` predicate, multi-`as` chaining with `|`,
  `match`/`precede` keyword aliases, `[attr]` add/toggle, between attr forms
- Runtime: per-element listener registry + hs-deactivate!, attr toggle
  variants, set-inner-html boots subtree, hs-append polymorphic on
  string/list/element, default? / array-set! / query-all-in / list-set
  via take+drop, hs-script idempotence guard
- Integration: skip reserved (me/it/event/you/yourself) when collecting vars
- Tokenizer: emit `--` comments and `|` op
- Test framework + conformance runner updates; new tests/hs-run-filtered.js
  (single-process Node runner using OCaml VM step-limit to bound infinite
  loops); generate-sx-conformance-dev.py improvements
- mcp_tree.ml + run_tests.ml: harness extensions
- .gitignore: top-level test-results/ (Playwright artifacts)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

spec/tests/test-framework.sx

@@ -18,11 +18,18 @@
 ;; 1. Test framework macros
 ;; --------------------------------------------------------------------------
 
-(defmacro deftest (name &rest body)
-  `(let ((result (try-call (fn () ,@body))))
-     (if (get result "ok")
-       (report-pass ,name)
-       (report-fail ,name (get result "error")))))
+(defmacro
+  deftest
+  (name &rest body)
+  (quasiquote
+    (when
+      (test-allowed? (unquote name))
+      (let
+        ((result (try-call (fn () (splice-unquote body)))))
+        (if
+          (get result "ok")
+          (report-pass (unquote name))
+          (report-fail (unquote name) (get result "error")))))))
 
 (defmacro defsuite (name &rest items)
   `(do (push-suite ,name)