Because you deployed the project source code, not the built project. If you want to deploy manually you need to build the project locally and deploy the output.
This is because you haven’t understood the tool you are using (Vite) and quite possibly haven’t read the documentation. If you read the topic I linked previously, you will find the solution to your issue (and links to the relevant Vite documentation.)
On another note, you will need to rename the project as Pinterest is a protected trademark and using such names without authorisation is a violation of Netlify’s terms (and law.) You will also want to refrain from using the Pinterest logo and name anywhere in the site.