WASM rebuild + playground page

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

sx/sx/playground.sx

@@ -1,18 +1,21 @@
-;; Playground — interactive REPL with lazy-loaded compiler
+;; Playground — demonstrates lazy module loading on navigation
 
 (defcomp ~playground/content (&key (title "Playground"))
   (~docs/page :title title
     (h1 "Playground")
-    (p "An interactive SX REPL. The compiler module loads on demand when you navigate here.")
+    (p "This page lazy-loads the " (code "sx freeze") " and " (code "sx compiler")
+       " modules when you navigate here. They are NOT loaded at boot.")
     (span :data-sx-island "playground/repl"
       (div (~tw :tokens "mt-6 border border-stone-200 rounded-lg overflow-hidden")
         (div (~tw :tokens "bg-stone-100 px-4 py-2 text-sm font-mono text-stone-500")
           "sx> ")
         (div (~tw :tokens "p-4 font-mono text-sm min-h-[120px] text-stone-400")
-          "Loading compiler...")))))
+          "Loading modules...")))))
 
 (defisland ~playground/repl ()
   (do
+    ;; These two modules are NOT in the boot manifest — they load on demand
+    (load-library! "sx freeze")
     (load-library! "sx compiler")
     (let ((input (signal ""))
           (output (signal "(ready)"))