Fix browser: set render-active in DOM adapter + on adapter init

Browser always evaluates in render context — _renderMode must be true
when DOM adapter is loaded, and render-to-dom must call set-render-active!.
Fixes 'Undefined symbol: <>' error in browser.

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

shared/static/scripts/sx-browser.js

@@ -14,7 +14,7 @@
   // =========================================================================
 
   var NIL = Object.freeze({ _nil: true, toString: function() { return "nil"; } });
-  var SX_VERSION = "2026-03-11T03:49:41Z";
+  var SX_VERSION = "2026-03-11T03:51:49Z";
 
   function isNil(x) { return x === NIL || x === null || x === undefined; }
   function isSxTruthy(x) { return x !== false && !isNil(x); }
@@ -1537,7 +1537,8 @@ return result; }, args);
   var MATH_NS = "http://www.w3.org/1998/Math/MathML";
 
   // render-to-dom
-  var renderToDom = function(expr, env, ns) { return (function() { var _m = typeOf(expr); if (_m == "nil") return createFragment(); if (_m == "boolean") return createFragment(); if (_m == "raw-html") return domParseHtml(rawHtmlContent(expr)); if (_m == "string") return createTextNode(expr); if (_m == "number") return createTextNode((String(expr))); if (_m == "symbol") return renderToDom(trampoline(evalExpr(expr, env)), env, ns); if (_m == "keyword") return createTextNode(keywordName(expr)); if (_m == "dom-node") return expr; if (_m == "dict") return createFragment(); if (_m == "list") return (isSxTruthy(isEmpty(expr)) ? createFragment() : renderDomList(expr, env, ns)); return (isSxTruthy(isSignal(expr)) ? (isSxTruthy(_islandScope) ? reactiveText(expr) : createTextNode((String(deref(expr))))) : createTextNode((String(expr)))); })(); };
+  var renderToDom = function(expr, env, ns) { setRenderActiveB(true);
+return (function() { var _m = typeOf(expr); if (_m == "nil") return createFragment(); if (_m == "boolean") return createFragment(); if (_m == "raw-html") return domParseHtml(rawHtmlContent(expr)); if (_m == "string") return createTextNode(expr); if (_m == "number") return createTextNode((String(expr))); if (_m == "symbol") return renderToDom(trampoline(evalExpr(expr, env)), env, ns); if (_m == "keyword") return createTextNode(keywordName(expr)); if (_m == "dom-node") return expr; if (_m == "dict") return createFragment(); if (_m == "list") return (isSxTruthy(isEmpty(expr)) ? createFragment() : renderDomList(expr, env, ns)); return (isSxTruthy(isSignal(expr)) ? (isSxTruthy(_islandScope) ? reactiveText(expr) : createTextNode((String(deref(expr))))) : createTextNode((String(expr)))); })(); };
 
   // render-dom-list
   var renderDomList = function(expr, env, ns) { return (function() {
@@ -3459,6 +3460,7 @@ return (isSxTruthy((_batchDepth == 0)) ? (function() {
 
   // Register DOM adapter as the render dispatch target for the evaluator.
   _renderExprFn = function(expr, env) { return renderToDom(expr, env, null); };
+  _renderMode = true;  // Browser always evaluates in render context.
 
   var SVG_NS = "http://www.w3.org/2000/svg";
   var MATH_NS = "http://www.w3.org/1998/Math/MathML";

shared/sx/ref/adapter-dom.sx

@@ -20,6 +20,7 @@
 
 (define render-to-dom
   (fn (expr env ns)
+    (set-render-active! true)
     (case (type-of expr)
       ;; nil / boolean false / boolean true → empty fragment
       "nil"       (create-fragment)

shared/sx/ref/bootstrap_js.py

@@ -2776,6 +2776,7 @@ PLATFORM_DOM_JS = """
 
   // Register DOM adapter as the render dispatch target for the evaluator.
   _renderExprFn = function(expr, env) { return renderToDom(expr, env, null); };
+  _renderMode = true;  // Browser always evaluates in render context.
 
   var SVG_NS = "http://www.w3.org/2000/svg";
   var MATH_NS = "http://www.w3.org/1998/Math/MathML";