refactor: replace next-auth with better-auth dependency

package.json

@@ -9,13 +9,13 @@
     "lint": "next lint"
   },
   "dependencies": {
-    "@auth/drizzle-adapter": "^1.10.0",
     "@radix-ui/react-checkbox": "^1.3.3",
     "@radix-ui/react-dialog": "^1.1.15",
     "@radix-ui/react-dropdown-menu": "^2.1.16",
     "@radix-ui/react-label": "^2.1.7",
     "@radix-ui/react-select": "^2.2.6",
     "@radix-ui/react-slot": "^1.2.3",
+    "better-auth": "^1.6.0",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "date-fns": "^4.1.0",
@@ -26,7 +26,6 @@
     "lucide-react": "^0.539.0",
     "nanoid": "^5.1.5",
     "next": "15.4.10",
-    "next-auth": "^5.0.0-beta.29",
     "next-themes": "^0.4.6",
     "pg": "^8.16.3",
     "postgres": "^3.4.7",