Initial TanStack Start port of nextjs-startup

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/components/ui/spinner.tsx

@@ -0,0 +1,10 @@
+import { cn } from "@/lib/utils"
+import { RiLoader4Line } from "@remixicon/react"
+
+function Spinner({ className, ...props }: React.ComponentProps<typeof RiLoader4Line>) {
+  return (
+    <RiLoader4Line data-slot="spinner" role="status" aria-label="Loading" className={cn("size-4 animate-spin", className)} {...props} />
+  )
+}
+
+export { Spinner }