feat(web): Next.js 15 app shell, auth, i18n, base UI

App Router setup with next-intl (en/fr), Better Auth wiring, shadcn/ui components,
Tailwind, AES-256-GCM encrypt util, Redis rate limiter, tier limit checker,
site_settings helper for runtime .env overrides.

apps/web/components/ui/label.tsx

@@ -0,0 +1,20 @@
+"use client"
+
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+function Label({ className, ...props }: React.ComponentProps<"label">) {
+  return (
+    <label
+      data-slot="label"
+      className={cn(
+        "flex items-center gap-2 text-sm leading-none font-medium select-none group-data-[disabled=true]:pointer-events-none group-data-[disabled=true]:opacity-50 peer-disabled:cursor-not-allowed peer-disabled:opacity-50",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export { Label }