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/accordion.tsx

@@ -0,0 +1,66 @@
+"use client"
+
+import * as React from "react"
+import * as AccordionPrimitive from "@radix-ui/react-accordion"
+import { ChevronDownIcon } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+function Accordion({
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Root>) {
+  return <AccordionPrimitive.Root data-slot="accordion" {...props} />
+}
+
+function AccordionItem({
+  className,
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Item>) {
+  return (
+    <AccordionPrimitive.Item
+      data-slot="accordion-item"
+      className={cn("border-b last:border-b-0", className)}
+      {...props}
+    />
+  )
+}
+
+function AccordionTrigger({
+  className,
+  children,
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Trigger>) {
+  return (
+    <AccordionPrimitive.Header className="flex">
+      <AccordionPrimitive.Trigger
+        data-slot="accordion-trigger"
+        className={cn(
+          "focus-visible:border-ring focus-visible:ring-ring/50 flex flex-1 items-start justify-between gap-4 rounded-md py-4 text-left text-sm font-medium transition-all outline-none hover:underline focus-visible:ring-[3px] disabled:pointer-events-none disabled:opacity-50 [&[data-state=open]>svg]:rotate-180",
+          className
+        )}
+        {...props}
+      >
+        {children}
+        <ChevronDownIcon className="text-muted-foreground pointer-events-none size-4 shrink-0 translate-y-0.5 transition-transform duration-200" />
+      </AccordionPrimitive.Trigger>
+    </AccordionPrimitive.Header>
+  )
+}
+
+function AccordionContent({
+  className,
+  children,
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Content>) {
+  return (
+    <AccordionPrimitive.Content
+      data-slot="accordion-content"
+      className="data-[state=closed]:animate-accordion-up data-[state=open]:animate-accordion-down overflow-hidden text-sm"
+      {...props}
+    >
+      <div className={cn("pt-0 pb-4", className)}>{children}</div>
+    </AccordionPrimitive.Content>
+  )
+}
+
+export { Accordion, AccordionItem, AccordionTrigger, AccordionContent }