Add reusable UI components: Textarea, Input, Label, and Switch

Introduce four reusable components (Textarea, Input, Label, Switch) with consistent styling and accessibility support. These components streamline UI development and follow best practices for design and interactivity.

frontend/src/components/ui/switch.tsx

@@ -0,0 +1,31 @@
+"use client"
+
+import * as React from "react"
+import * as SwitchPrimitive from "@radix-ui/react-switch"
+
+import { cn } from "@/lib/utils"
+
+function Switch({
+  className,
+  ...props
+}: React.ComponentProps<typeof SwitchPrimitive.Root>) {
+  return (
+    <SwitchPrimitive.Root
+      data-slot="switch"
+      className={cn(
+        "peer data-[state=checked]:bg-primary data-[state=unchecked]:bg-input focus-visible:border-ring focus-visible:ring-ring/50 inline-flex h-5 w-9 shrink-0 items-center rounded-full border-2 border-transparent shadow-xs transition-all outline-none focus-visible:ring-[3px] disabled:cursor-not-allowed disabled:opacity-50",
+        className
+      )}
+      {...props}
+    >
+      <SwitchPrimitive.Thumb
+        data-slot="switch-thumb"
+        className={cn(
+          "bg-background pointer-events-none block size-4 rounded-full ring-0 shadow-lg transition-transform data-[state=checked]:translate-x-4 data-[state=unchecked]:translate-x-0"
+        )}
+      />
+    </SwitchPrimitive.Root>
+  )
+}
+
+export { Switch }