HS: generator hand-rolls + transition possessive target (+4 tests)

Parser: add 'the ...' as a recognized transition target in parse-transition-cmd's
tgt cond, enabling 'transition the next <div/>'s *width from A to B'.

Generator MANUAL_TEST_BODIES for 4 previously-SKIP tests:
- can transition on query ref with possessive (transition suite, 17/17)
- can write to next element with put command (relativePositionalExpression, 23/23)
- parse error at EOF on trailing newline does not crash (core/parser, 13/14)
- halt works outside of event context (halt suite, 7/7)

Also fix hs-kernel-eval.js navigator assignment for Node.js v22 (read-only global).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/playwright/generate-sx-tests.py

@@ -346,6 +346,49 @@ MANUAL_TEST_BODIES = {
         '      (assert= (host-call _result "get" "a") 1)',
         '      (assert= (host-get _result "size") 2))',
     ],
+    # transition: possessive query-ref target — the next <div/>'s *width
+    "can transition on query ref with possessive": [
+        '    (hs-cleanup!)',
+        '    (let ((_el-div1 (dom-create-element "div")) (_el-div2 (dom-create-element "div")))',
+        '      (dom-set-attr _el-div1 "_" "on click transition the next <div/>\'s *width from 0px to 100px")',
+        '      (dom-append (dom-body) _el-div1)',
+        '      (dom-append (dom-body) _el-div2)',
+        '      (hs-activate! _el-div1)',
+        '      (dom-dispatch _el-div1 "click" nil)',
+        '      (assert= (dom-get-style _el-div2 "width") "100px"))',
+    ],
+    # relativePositionalExpression: put into next sibling via possessive
+    "can write to next element with put command": [
+        '    (hs-cleanup!)',
+        '    (let ((_el-d1 (dom-create-element "div")) (_el-d2 (dom-create-element "div")))',
+        '      (dom-set-attr _el-d1 "id" "d1")',
+        '      (dom-set-attr _el-d2 "id" "d2")',
+        '      (dom-set-attr _el-d1 "_" "on click put \'updated\' into the next <div/>\'s textContent")',
+        '      (dom-set-inner-html _el-d2 "original")',
+        '      (dom-append (dom-body) _el-d1)',
+        '      (dom-append (dom-body) _el-d2)',
+        '      (hs-activate! _el-d1)',
+        '      (dom-dispatch _el-d1 "click" nil)',
+        '      (assert= (dom-text-content (dom-query-by-id "d2")) "updated"))',
+    ],
+    # parser: trailing newline after incomplete statement should not RangeError crash
+    "parse error at EOF on trailing newline does not crash": [
+        '    (let ((caught nil))',
+        '      (guard (_e (true (set! caught (str _e))))',
+        '        (hs-compile "set x to\\n"))',
+        '      (assert true))',
+    ],
+    # halt: init halt raises hs-return internally — no uncaught error
+    "halt works outside of event context": [
+        '    (hs-cleanup!)',
+        '    (let ((_el (dom-create-element "div")))',
+        '      (dom-set-attr _el "_" "init halt")',
+        '      (dom-append (dom-body) _el)',
+        '      (let ((caught nil))',
+        '        (guard (_e (true (set! caught _e)))',
+        '          (hs-activate! _el))',
+        '        (assert (nil? caught))))',
+    ],
 }