fix: update dependencies in package.json and adjust file permissions

- Updated @vitejs/plugin-vue to version 5.1.4 and vite to version 6.0.1 in package.json.
- Changed file permissions for multiple files to 755.
- Modified router index.js to ensure proper imports.
- Enhanced ChatPage.vue to include logging for message sending.
- Updated LoginPage.vue to change variable from 'identifier' to 'pseudo' and adjusted the login function accordingly.
- Cleaned up unused styles in RegisterPage.vue and ValidateEmailPage.vue.
