HS: parse-cmd pseudo-command validation — only enforce callable check in non-span mode

In span mode (hs-parse-ast), parse-cmd is used to extract source info from
arbitrary expressions like literals and property access — not just callables.
Guard the "expected function call" error with hs-span-mode so span mode
passes all expression types through, while execution mode still rejects
non-callable expressions.

Also handle span mode's hs-ast dict nodes (kind="call") in the callable?
check, since method calls are wrapped in span mode.

lib/hyperscript/parser.sx

@@ -2874,15 +2874,12 @@
               (true
                 (let
                   ((expr (parse-expr)))
-                  (if
+                  (let
-                    (or
+                    ((callable? (if (and (dict? expr) (get expr :hs-ast)) (= (get expr :kind) "call") (or (= (first expr) (quote call)) (= (first expr) (quote method-call))))))
-                      (= (first expr) (quote call))
+                    (if
-                      (= (first expr) (quote method-call)))
+                      (or callable? hs-span-mode)
-                    expr
+                      expr
-                    (error
+                      (error "Invalid command — expected a function call")))))))))
-                      (str
-                        "Invalid command — expected a function call, got: "
-                        (str (first expr)))))))))))
       (define
         parse-cmd-list
         (fn