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>

shared/static/wasm/sx/hs-integration.sx

@@ -16,6 +16,14 @@
     (fn
       (sx)
       (define vars (list))
+      (define
+        reserved
+        (list
+          (quote me)
+          (quote it)
+          (quote event)
+          (quote you)
+          (quote yourself)))
       (define
         walk
         (fn
@@ -30,7 +38,9 @@
               (let
                 ((name (nth node 1)))
                 (when
-                  (not (some (fn (v) (= v name)) vars))
+                  (and
+                    (not (some (fn (v) (= v name)) vars))
+                    (not (some (fn (v) (= v name)) reserved)))
                   (set! vars (cons name vars)))))
             (for-each walk node))))
       (walk sx)