chore: add npm support metadata

[brohebot]

Summary

• add standard npm support metadata to package.json
• point repository to this public GitHub repo
• add bugs.url for the issue tracker

Testing

• node -e "const p=require('./package.json'); if(p.repository?.type!=='git'||p.repository?.url!=='git+https://github.com/stripe/terminal-js.git'||p.bugs?.url!=='https://github.com/stripe/terminal-js/issues'||p.homepage!=='https://stripe.com/docs/terminal/sdk/js') process.exit(1); console.log(JSON.stringify({homepage:p.homepage,repository:p.repository,bugs:p.bugs}, null, 2))"
• npm pack --dry-run --ignore-scripts --json
• git diff --check

[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[brohebot]

Friendly follow-up here. This one only updates package metadata, so if you want anything tweaked around the manifest shape, I can adjust it quickly.