Introduce comprehensive user management functionality for admin

- Added React Query hooks for user-related actions: `useCreateUser`, `useUpdateUser`, `useDeleteUser`, `useActivateUser`, `useDeactivateUser`, and `useBulkUserAction`.
- Implemented primary user management components: `UserFormDialog`, `UserManagementContent`, `UserListTable`, `BulkActionToolbar`, and `UserActionMenu`.
- Replaced placeholder content on the Users page with full user management capabilities.
- Included role-based validation, search, pagination, filtering, and bulk operations.
- Enhanced form validation with `zod` schema for robust user input handling.
- Added feedback mechanisms (toasts and alert dialogs) for user actions.
- Improved UI accessibility and usability across the admin user management feature.

frontend/src/components/ui/alert-dialog.tsx

@@ -0,0 +1,157 @@
+"use client"
+
+import * as React from "react"
+import * as AlertDialogPrimitive from "@radix-ui/react-alert-dialog"
+
+import { cn } from "@/lib/utils/index"
+import { buttonVariants } from "@/components/ui/button"
+
+function AlertDialog({
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Root>) {
+  return <AlertDialogPrimitive.Root data-slot="alert-dialog" {...props} />
+}
+
+function AlertDialogTrigger({
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Trigger>) {
+  return (
+    <AlertDialogPrimitive.Trigger data-slot="alert-dialog-trigger" {...props} />
+  )
+}
+
+function AlertDialogPortal({
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Portal>) {
+  return (
+    <AlertDialogPrimitive.Portal data-slot="alert-dialog-portal" {...props} />
+  )
+}
+
+function AlertDialogOverlay({
+  className,
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Overlay>) {
+  return (
+    <AlertDialogPrimitive.Overlay
+      data-slot="alert-dialog-overlay"
+      className={cn(
+        "data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 fixed inset-0 z-50 bg-black/50",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AlertDialogContent({
+  className,
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Content>) {
+  return (
+    <AlertDialogPortal>
+      <AlertDialogOverlay />
+      <AlertDialogPrimitive.Content
+        data-slot="alert-dialog-content"
+        className={cn(
+          "bg-background data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 fixed top-[50%] left-[50%] z-50 grid w-full max-w-[calc(100%-2rem)] translate-x-[-50%] translate-y-[-50%] gap-4 rounded-lg border p-6 shadow-lg duration-200 sm:max-w-lg",
+          className
+        )}
+        {...props}
+      />
+    </AlertDialogPortal>
+  )
+}
+
+function AlertDialogHeader({
+  className,
+  ...props
+}: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="alert-dialog-header"
+      className={cn("flex flex-col gap-2 text-center sm:text-left", className)}
+      {...props}
+    />
+  )
+}
+
+function AlertDialogFooter({
+  className,
+  ...props
+}: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="alert-dialog-footer"
+      className={cn(
+        "flex flex-col-reverse gap-2 sm:flex-row sm:justify-end",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AlertDialogTitle({
+  className,
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Title>) {
+  return (
+    <AlertDialogPrimitive.Title
+      data-slot="alert-dialog-title"
+      className={cn("text-lg font-semibold", className)}
+      {...props}
+    />
+  )
+}
+
+function AlertDialogDescription({
+  className,
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Description>) {
+  return (
+    <AlertDialogPrimitive.Description
+      data-slot="alert-dialog-description"
+      className={cn("text-muted-foreground text-sm", className)}
+      {...props}
+    />
+  )
+}
+
+function AlertDialogAction({
+  className,
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Action>) {
+  return (
+    <AlertDialogPrimitive.Action
+      className={cn(buttonVariants(), className)}
+      {...props}
+    />
+  )
+}
+
+function AlertDialogCancel({
+  className,
+  ...props
+}: React.ComponentProps<typeof AlertDialogPrimitive.Cancel>) {
+  return (
+    <AlertDialogPrimitive.Cancel
+      className={cn(buttonVariants({ variant: "outline" }), className)}
+      {...props}
+    />
+  )
+}
+
+export {
+  AlertDialog,
+  AlertDialogPortal,
+  AlertDialogOverlay,
+  AlertDialogTrigger,
+  AlertDialogContent,
+  AlertDialogHeader,
+  AlertDialogFooter,
+  AlertDialogTitle,
+  AlertDialogDescription,
+  AlertDialogAction,
+  AlertDialogCancel,
+}

frontend/src/components/ui/button.tsx

@@ -2,7 +2,7 @@ import * as React from "react"
 import { Slot } from "@radix-ui/react-slot"
 import { cva, type VariantProps } from "class-variance-authority"
 
-import { cn } from "@/lib/utils"
+import { cn } from "@/lib/utils/index"
 
 const buttonVariants = cva(
   "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:pointer-events-none disabled:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0",