feat: add not-found.tsx to handle incorrect routes

[enggsatyamraj]

PR Fixes:

• 1 Added not-found.tsx to handle incorrect routes
• 2 Improved user experience by providing a proper 404 page for invalid URLs

Resolves #[Issue Number if there]

Checklist before requesting a review

• [ x ] I have performed a self-review of my code
• [ x ] I assure there is no similar/duplicate pull request regarding same issue
• [ x ] I have attached a screenshot of the 404 page for reference

[devsargam]

nice

[enggsatyamraj]

@devsargam @hkirat Is it working fine?