Upgrade Next.js to 15.5.9 (#326)

Co-authored-by: Claude <noreply@anthropic.com>

Author: KMKoushik

apps/marketing/package.json

@@ -17,7 +17,7 @@
     "@usesend/email-editor": "workspace:*",
     "@usesend/ui": "workspace:*",
     "iconoir-react": "^7.11.0",
-    "next": "15.5.8",
+    "next": "15.5.9",
     "react": "19.1.0",
     "react-dom": "19.1.0"
   },

apps/web/package.json

@@ -52,7 +52,7 @@
     "lucide-react": "^0.503.0",
     "mime-types": "^3.0.1",
     "nanoid": "^5.1.5",
-    "next": "15.5.8",
+    "next": "15.5.9",
     "next-auth": "^4.24.11",
     "nodemailer": "^7.0.3",
     "pino": "^9.7.0",