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/breadcrumb.tsx

@@ -0,0 +1,109 @@
+import * as React from "react"
+import { Slot } from "@radix-ui/react-slot"
+import { ChevronRight, MoreHorizontal } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+function Breadcrumb({ ...props }: React.ComponentProps<"nav">) {
+  return <nav aria-label="breadcrumb" data-slot="breadcrumb" {...props} />
+}
+
+function BreadcrumbList({ className, ...props }: React.ComponentProps<"ol">) {
+  return (
+    <ol
+      data-slot="breadcrumb-list"
+      className={cn(
+        "text-muted-foreground flex flex-wrap items-center gap-1.5 text-sm break-words sm:gap-2.5",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function BreadcrumbItem({ className, ...props }: React.ComponentProps<"li">) {
+  return (
+    <li
+      data-slot="breadcrumb-item"
+      className={cn("inline-flex items-center gap-1.5", className)}
+      {...props}
+    />
+  )
+}
+
+function BreadcrumbLink({
+  asChild,
+  className,
+  ...props
+}: React.ComponentProps<"a"> & {
+  asChild?: boolean
+}) {
+  const Comp = asChild ? Slot : "a"
+
+  return (
+    <Comp
+      data-slot="breadcrumb-link"
+      className={cn("hover:text-foreground transition-colors", className)}
+      {...props}
+    />
+  )
+}
+
+function BreadcrumbPage({ className, ...props }: React.ComponentProps<"span">) {
+  return (
+    <span
+      data-slot="breadcrumb-page"
+      role="link"
+      aria-disabled="true"
+      aria-current="page"
+      className={cn("text-foreground font-normal", className)}
+      {...props}
+    />
+  )
+}
+
+function BreadcrumbSeparator({
+  children,
+  className,
+  ...props
+}: React.ComponentProps<"li">) {
+  return (
+    <li
+      data-slot="breadcrumb-separator"
+      role="presentation"
+      aria-hidden="true"
+      className={cn("[&>svg]:size-3.5", className)}
+      {...props}
+    >
+      {children ?? <ChevronRight />}
+    </li>
+  )
+}
+
+function BreadcrumbEllipsis({
+  className,
+  ...props
+}: React.ComponentProps<"span">) {
+  return (
+    <span
+      data-slot="breadcrumb-ellipsis"
+      role="presentation"
+      aria-hidden="true"
+      className={cn("flex size-9 items-center justify-center", className)}
+      {...props}
+    >
+      <MoreHorizontal className="size-4" />
+      <span className="sr-only">More</span>
+    </span>
+  )
+}
+
+export {
+  Breadcrumb,
+  BreadcrumbList,
+  BreadcrumbItem,
+  BreadcrumbLink,
+  BreadcrumbPage,
+  BreadcrumbSeparator,
+  BreadcrumbEllipsis,
+}