chore(deps): Update dependencies and enhance API error handling

- Added '@vercel/analytics' to package.json for improved analytics tracking.
- Updated 'next' version from 15.0.2 to 15.0.3 to incorporate the latest features and fixes.
- Refactored API routes for invitations and studies to improve error handling and response structure.
- Enhanced permission checks in the invitations and studies API to ensure proper access control.
- Removed the participants dashboard page as part of a restructuring effort.
- Updated the database schema to include environment settings for users and studies.
- Improved the dashboard components to handle loading states and display statistics more effectively.

package.json

@@ -25,6 +25,7 @@
     "@radix-ui/react-slot": "^1.1.0",
     "@radix-ui/react-tabs": "^1.1.1",
     "@types/nodemailer": "^6.4.17",
+    "@vercel/analytics": "^1.4.1",
     "@vercel/postgres": "^0.10.0",
     "class-variance-authority": "^0.7.0",
     "clsx": "^2.1.1",
@@ -32,7 +33,7 @@
     "dotenv": "^16.4.5",
     "drizzle-orm": "^0.36.3",
     "lucide-react": "^0.454.0",
-    "next": "15.0.2",
+    "next": "15.0.3",
     "ngrok": "5.0.0-beta.2",
     "nodemailer": "^6.9.16",
     "react": "^18.3.1",