HS parser: add 'your' as alias for 'my' in property access

In hyperscript, 'your' refers to the element in a 'tell' scope,
functioning identically to 'my' for property access. Fixes
"Expected into/before/after/at" parse errors in tell commands.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/hyperscript/parser.sx

@@ -158,7 +158,7 @@
                 (do
                   (adv!)
                   (list (make-symbol ".") (list (quote event)) "detail")))
-              ((and (= typ "keyword") (= val "my"))
+              ((and (= typ "keyword") (or (= val "my") (= val "your")))
                 (do (adv!) (parse-poss-tail (list (quote me)))))
               ((and (= typ "keyword") (= val "its"))
                 (do (adv!) (parse-poss-tail (list (quote it)))))