Update dependencies and fix security advisories

- next 16.3.7, react/react-dom 19.3.0, tailwindcss 4.3.3, sharp 0.35.5,
  lucide-react 1.49.0 and other minor updates
- npm audit: 10 vulnerabilities (2 critical: next, tar) -> 0
- Remove unused motion and @next/env
- Stay on ESLint 9: ESLint 10 crashes in eslint-config-next's plugins

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

package.json

@@ -9,24 +9,22 @@
     "lint": "eslint ."
   },
   "dependencies": {
-    "@next/env": "^16.2.10",
-    "@radix-ui/react-accordion": "^1.2.3",
+    "@radix-ui/react-accordion": "^1.2.20",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
-    "lucide-react": "^0.487.0",
-    "motion": "^11.16.0",
-    "next": "^16.2.10",
-    "react": "^19.2.7",
-    "react-dom": "^19.2.7",
-    "sharp": "^0.33.5",
-    "tailwind-merge": "^3.1.0",
-    "tw-animate-css": "^1.2.5"
+    "lucide-react": "^1.49.0",
+    "next": "^16.3.7",
+    "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": {
-    "@tailwindcss/postcss": "^4.1.1",
+    "@tailwindcss/postcss": "^4.3.3",
     "eslint": "^9.39.5",
-    "eslint-config-next": "^16.2.10",
-    "postcss": "^8.4.49",
-    "tailwindcss": "^4.1.1"
+    "eslint-config-next": "^16.3.7",
+    "postcss": "^8.5.28",
+    "tailwindcss": "^4.3.3"
   }
 }