Migrate to the cn package

- Ran `npx shadcn@latest migrate cn`: swaps clsx + tailwind-merge for cn
- Import cn from "cn" everywhere (matches what `shadcn add` now writes)
  and remove the src/lib/utils.js re-export shim

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/components/ui/table.jsx

@@ -1,7 +1,7 @@
 "use client"
 
 import * as React from "react"
-import { cn } from "@/lib/utils"
+import { cn } from "cn"
 
 function Table({
   className,