fix(csr): consume document binding metadata

packages/csr/src/reactive-runtime.ts

@@ -3537,6 +3537,20 @@ export const REACTIVE_RUNTIME = String.raw`
   function hydrateScopes(root) {
     var host = root || document;
 
+    // The document shell can contain server-resolved attributes such as
+    // lang={language} and data-theme={theme}. It has no component scope and
+    // therefore no client-side binding to retain; consume its compiler markers
+    // separately from component hydration.
+    if (host === document || host === document.documentElement) {
+      Array.prototype.slice
+        .call(document.documentElement.attributes)
+        .forEach(function (attribute) {
+          if (attribute.name.indexOf("data-wrn-bind-") === 0) {
+            document.documentElement.removeAttribute(attribute.name);
+          }
+        });
+    }
+
     var scopeSelector =
       "[data-scope], [data-wrn-scope]";
 

packages/csr/test/reactive.test.ts

@@ -549,6 +549,25 @@ test("hydration consumes private scope, behavior, and binding metadata", () => {
   expect(button.getAttribute("aria-expanded")).toBe("true");
 });
 
+test("hydration removes server-resolved document binding metadata", () => {
+  const win = mount(`<main>Document content</main>`);
+  const root = win.document.documentElement;
+  root.setAttribute("lang", "en");
+  root.setAttribute("data-theme", "dark");
+  root.setAttribute("data-wrn-bind-0", '["lang","{language}"]');
+  root.setAttribute("data-wrn-bind-1", '["data-theme","{theme}"]');
+
+  const runtime = win as unknown as {
+    __wrnexusHydrateScopes?: (root: unknown) => void;
+  };
+  runtime.__wrnexusHydrateScopes?.(win.document);
+
+  expect(root.getAttribute("lang")).toBe("en");
+  expect(root.getAttribute("data-theme")).toBe("dark");
+  expect(root.hasAttribute("data-wrn-bind-0")).toBe(false);
+  expect(root.hasAttribute("data-wrn-bind-1")).toBe(false);
+});
+
 test("compiled client functions are not overwritten by fallback behavior parsing", () => {
   const behavior = Buffer.from(
     JSON.stringify({