spec: gensym + symbol interning — *gensym-counter*, string->symbol, symbol->string, intern

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

hosts/javascript/platform.py

@@ -1663,6 +1663,8 @@ PLATFORM_JS_POST = '''
   var vectorLength = PRIMITIVES["vector-length"];
   var vectorRef = PRIMITIVES["vector-ref"];
   var reverse = PRIMITIVES["reverse"];
+  var stringToSymbol = PRIMITIVES["string->symbol"];
+  var symbolToString = PRIMITIVES["symbol->string"];
   function zip(a, b) { var r = []; for (var i = 0; i < Math.min(a.length, b.length); i++) r.push([a[i], b[i]]); return r; }
   function append_b(arr, x) { arr.push(x); return arr; }
   var apply = function(f, args) {