Fix dialog SSR crash by gating DialogPortal to client

DialogPortal aliased Radix's Portal directly, which calls
createPortal(children, document.body) during render. Static
prerendering (e.g. /about via InquiryDialog) has no document
global and threw "document is not defined". Wrap it so the
portal only mounts client-side.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012Exmd6Wn13TGp1sArgK7y4

components/ui/dialog.tsx

@@ -10,7 +10,26 @@ const Dialog = DialogPrimitive.Root;
 
 const DialogTrigger = DialogPrimitive.Trigger;
 
-const DialogPortal = DialogPrimitive.Portal;
+// Only render the portal on the client. During SSR/static prerendering the
+// `document` global doesn't exist, and React Dom's createPortal(children,
+// document.body) inside Radix's Portal would throw "document is not defined".
+const DialogPortal = ({
+  children,
+  ...props
+}: React.ComponentPropsWithoutRef<typeof DialogPrimitive.Portal>) => {
+  const [mounted, setMounted] = React.useState(false);
+
+  React.useEffect(() => {
+    setMounted(true);
+  }, []);
+
+  if (!mounted) {
+    return null;
+  }
+
+  return <DialogPrimitive.Portal {...props}>{children}</DialogPrimitive.Portal>;
+};
+DialogPortal.displayName = DialogPrimitive.Portal.displayName;
 
 const DialogClose = DialogPrimitive.Close;