feat: add UI components including Skeleton, Slider, Toaster, Switch, Table, Tabs, Textarea, Toggle Group, Toggle, Tooltip, and User Avatar

- Implemented Skeleton component for loading states.
- Added Slider component using Radix UI for customizable sliders.
- Created Toaster component for notifications with theme support.
- Developed Switch component for toggle functionality.
- Introduced Table component with subcomponents for structured data display.
- Built Tabs component for tabbed navigation.
- Added Textarea component for multi-line text input.
- Implemented Toggle Group and Toggle components for grouped toggle buttons.
- Created Tooltip component for displaying additional information on hover.
- Added User Avatar component for displaying user images with fallback.
- Implemented useIsMobile hook for responsive design.
- Created API utility functions for user and thought data fetching.
- Added utility function for class name merging.
- Updated package.json with new dependencies for UI components and utilities.
- Added TypeScript configuration for path aliasing.

thoughts-frontend/components/ui/card.tsx

@@ -0,0 +1,92 @@
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+function Card({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="card"
+      className={cn(
+        "bg-card text-card-foreground flex flex-col gap-6 rounded-xl border py-6 shadow-sm",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function CardHeader({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="card-header"
+      className={cn(
+        "@container/card-header grid auto-rows-min grid-rows-[auto_auto] items-start gap-1.5 px-6 has-data-[slot=card-action]:grid-cols-[1fr_auto] [.border-b]:pb-6",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function CardTitle({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="card-title"
+      className={cn("leading-none font-semibold", className)}
+      {...props}
+    />
+  )
+}
+
+function CardDescription({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="card-description"
+      className={cn("text-muted-foreground text-sm", className)}
+      {...props}
+    />
+  )
+}
+
+function CardAction({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="card-action"
+      className={cn(
+        "col-start-2 row-span-2 row-start-1 self-start justify-self-end",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function CardContent({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="card-content"
+      className={cn("px-6", className)}
+      {...props}
+    />
+  )
+}
+
+function CardFooter({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="card-footer"
+      className={cn("flex items-center px-6 [.border-t]:pt-6", className)}
+      {...props}
+    />
+  )
+}
+
+export {
+  Card,
+  CardHeader,
+  CardFooter,
+  CardTitle,
+  CardAction,
+  CardDescription,
+  CardContent,
+}