refactor: update sidebar.js to use underscore for unused event parameter

refactor: update chat.js to use underscore for unused index parameter

refactor: update multiselect.js to simplify function definitions and improve readability

refactor: update products.js to use underscore for unused variables

refactor: update timeline.js to use underscore for unused timeline variable

fix: update sidebar.hbs to correct navigation links for various pages

- Updated package.json to version 3.0.0
- Upgraded various dependencies including Bootstrap, Vite, Sass, and FullCalendar packages
- Added ESLint configuration with Prettier integration
- Created CHANGELOG.md to document changes and improvements
- Updated vite.config.js to reflect new version
- Enhanced developer experience with improved documentation and build performance