Improve sidebar, new chat, and share dialog (#190)

components/sidebar-toggle.tsx

@@ -0,0 +1,24 @@
+'use client'
+
+import * as React from 'react'
+
+import { useSidebar } from '@/lib/hooks/use-sidebar'
+import { Button } from '@/components/ui/button'
+import { IconSidebar } from '@/components/ui/icons'
+
+export function SidebarToggle() {
+  const { toggleSidebar } = useSidebar()
+
+  return (
+    <Button
+      variant="ghost"
+      className="-ml-2 hidden h-9 w-9 p-0 lg:flex"
+      onClick={() => {
+        toggleSidebar()
+      }}
+    >
+      <IconSidebar className="h-6 w-6" />
+      <span className="sr-only">Toggle Sidebar</span>
+    </Button>
+  )
+}