js-on-sx: 10 new Object.* globals (getPrototypeOf, create, is, hasOwn, defineProperty, ...)

Extends the Object global dict with:
- getPrototypeOf / setPrototypeOf — read/write __proto__ chain
- create(proto, props?) — builds new obj with proto and optional descriptors
- defineProperty / defineProperties — descriptor.value only (no getters/setters)
- getOwnPropertyNames / getOwnPropertyDescriptor(s) — simple shapes
- isExtensible / isFrozen / isSealed (permissive stubs)
- seal / preventExtensions (no-ops)
- is — SameValue (NaN is NaN, -0 vs +0 distinguished via inspect string)
- fromEntries — inverse of entries
- hasOwn — explicit owner check for string keys

9 new unit tests, 506/508 total.

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

lib/js/runtime.sx

@@ -2307,7 +2307,148 @@
 
 (define js-object-freeze (fn (o) o))
 
-(define Object {:entries js-object-entries :values js-object-values :freeze js-object-freeze :assign js-object-assign :keys js-object-keys})
+(define
+  js-object-get-prototype-of
+  (fn
+    (o)
+    (cond
+      ((= o nil) (error "TypeError: Cannot convert null to object"))
+      ((js-undefined? o)
+        (error "TypeError: Cannot convert undefined to object"))
+      ((dict? o)
+        (if (contains? (keys o) "__proto__") (get o "__proto__") nil))
+      (else nil))))
+
+(define
+  js-object-set-prototype-of
+  (fn
+    (o proto)
+    (begin (when (dict? o) (dict-set! o "__proto__" proto)) o)))
+
+(define
+  js-object-create
+  (fn
+    (&rest args)
+    (let
+      ((proto (if (empty? args) nil (nth args 0))))
+      (let
+        ((obj (dict)))
+        (begin
+          (when (not (= proto nil)) (dict-set! obj "__proto__" proto))
+          (when
+            (and (>= (len args) 2) (dict? (nth args 1)))
+            (for-each
+              (fn
+                (k)
+                (dict-set! obj k (get (get (nth args 1) k) "value")))
+              (keys (nth args 1))))
+          obj)))))
+
+(define
+  js-object-define-property
+  (fn
+    (o key desc)
+    (begin
+      (when
+        (and (dict? o) (dict? desc) (contains? (keys desc) "value"))
+        (dict-set! o (js-to-string key) (get desc "value")))
+      o)))
+
+(define
+  js-object-define-properties
+  (fn
+    (o descs)
+    (begin
+      (when
+        (and (dict? o) (dict? descs))
+        (for-each
+          (fn (k) (js-object-define-property o k (get descs k)))
+          (keys descs)))
+      o)))
+
+(define
+  js-object-get-own-property-names
+  (fn
+    (o)
+    (cond
+      ((list? o) (let ((r (list))) (begin (js-list-keys-loop o 0 r) r)))
+      ((dict? o) (js-object-keys o))
+      (else (list)))))
+
+(define
+  js-object-get-own-property-descriptor
+  (fn
+    (o key)
+    (if
+      (and (dict? o) (contains? (keys o) (js-to-string key)))
+      {:writable true :value (get o (js-to-string key)) :enumerable true :configurable true}
+      :js-undefined)))
+
+(define
+  js-object-get-own-property-descriptors
+  (fn
+    (o)
+    (let
+      ((out (dict)))
+      (begin
+        (when
+          (dict? o)
+          (for-each
+            (fn
+              (k)
+              (dict-set! out k (js-object-get-own-property-descriptor o k)))
+            (keys o)))
+        out))))
+
+(define js-object-is-extensible (fn (o) (not (js-undefined? o))))
+
+(define js-object-is-frozen (fn (o) false))
+
+(define js-object-is-sealed (fn (o) false))
+
+(define js-object-prevent-extensions (fn (o) o))
+
+(define js-object-seal (fn (o) o))
+
+(define
+  js-object-is
+  (fn
+    (a b)
+    (cond
+      ((and (js-number-is-nan a) (js-number-is-nan b)) true)
+      ((and (= a 0) (= b 0))
+        (let ((ia (inspect a)) (ib (inspect b))) (= ia ib)))
+      (else (js-strict-eq a b)))))
+
+(define
+  js-object-from-entries
+  (fn
+    (iter)
+    (let
+      ((out (dict)) (lst (js-iterable-to-list iter)))
+      (begin
+        (for-each
+          (fn
+            (pair)
+            (when
+              (and (list? pair) (>= (len pair) 2))
+              (dict-set! out (js-to-string (nth pair 0)) (nth pair 1))))
+          lst)
+        out))))
+
+(define
+  js-object-has-own
+  (fn
+    (o key)
+    (cond
+      ((dict? o) (contains? (keys o) (js-to-string key)))
+      ((list? o)
+        (let
+          ((idx (js-to-number key)))
+          (and (>= idx 0) (< idx (len o)) (integer? idx))))
+      (else false))))
+
+(define Object {:entries js-object-entries :defineProperties js-object-define-properties :preventExtensions js-object-prevent-extensions :prototype {} :values js-object-values :hasOwn js-object-has-own :freeze js-object-freeze :assign js-object-assign :isFrozen js-object-is-frozen :getOwnPropertyDescriptor js-object-get-own-property-descriptor :fromEntries js-object-from-entries :defineProperty js-object-define-property :setPrototypeOf js-object-set-prototype-of :getOwnPropertyNames js-object-get-own-property-names :getOwnPropertyDescriptors js-object-get-own-property-descriptors :create js-object-create :isExtensible js-object-is-extensible :is js-object-is :keys js-object-keys :getPrototypeOf js-object-get-prototype-of :isSealed js-object-is-sealed :seal js-object-seal})
 
 (define
   js-delete-prop