fix: correct repository url to electron-menubar for npm provenance

[afonsojramos]

Summary

The Publish to npm job for the 10.1.0 release failed with a provenance validation error:

npm error 422 Unprocessable Entity - Error verifying sigstore provenance bundle:
Failed to validate repository information: package.json: "repository.url" is
"git+https://github.com/gitify-app/menubar.git", expected to match
"https://github.com/gitify-app/electron-menubar" from provenance

The repo was renamed from gitify-app/menubar to gitify-app/electron-menubar, but package.json still pointed at the old name. npm provenance requires repository.url to exactly match the GitHub repository the build ran in, so publishing was rejected (10.1.0 was never published to npm; latest is still 10.0.2).

Changes

• Point homepage, bugs.url, and repository.url at gitify-app/electron-menubar
• Use the normalized git+https:// form for repository.url to clear the npm pkg fix warning

Follow-up

After merge, re-run the Publish workflow (workflow_dispatch on publish.yml, or via the next release) to publish 10.1.0 with the corrected provenance.