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]>

package-lock.json

@@ -9,14 +9,13 @@
       "version": "0.1.0",
       "dependencies": {
         "class-variance-authority": "^0.7.1",
-        "clsx": "^2.1.1",
+        "cn": "^0.4.0",
         "lucide-react": "^1.49.0",
         "next": "^16.3.7",
         "radix-ui": "^1.6.7",
         "react": "^19.3.0",
         "react-dom": "^19.3.0",
         "sharp": "^0.35.5",
-        "tailwind-merge": "^3.7.0",
         "tw-animate-css": "^1.4.0"
       },
       "devDependencies": {
@@ -4458,6 +4457,18 @@
         "node": ">=6"
       }
     },
+    "node_modules/cn": {
+      "version": "0.4.0",
+      "resolved": "https://registry.npmjs.org/cn/-/cn-0.4.0.tgz",
+      "integrity": "sha512-qOAeUhPwPzBxx6jaeQdo646XIKliKHc2j1ZF7Ngb1o0pJZKH5gq8FkA0aVdUdPFUDXNXyUCXpCtoJISo6dhizg==",
+      "license": "MIT",
+      "bin": {
+        "cn": "bin/cn.mjs"
+      },
+      "engines": {
+        "node": ">=20"
+      }
+    },
     "node_modules/color-convert": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",
@@ -8179,16 +8190,6 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
-    "node_modules/tailwind-merge": {
-      "version": "3.7.0",
-      "resolved": "https://registry.npmjs.org/tailwind-merge/-/tailwind-merge-3.7.0.tgz",
-      "integrity": "sha512-XPPUyAc+cvspz3lHTcR/QgPfW2A0lv/xQNIjX3HGhLR+Nq2lHaLq5MtTesHn8GUr3W3DguT2KT5x3NVgRtYwmA==",
-      "license": "MIT",
-      "funding": {
-        "type": "github",
-        "url": "https://github.com/sponsors/dcastil"
-      }
-    },
     "node_modules/tailwindcss": {
       "version": "4.3.3",
       "resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.3.3.tgz",