fix: pass signals to electron process

[liamcmitchell]

Description

Passes signals to electron process for cleaner exit.

Additional context

Matches behavior of electron start script: https://github.com/electron/electron/blob/31bc5ca903b35016649727326bf443ef11cc6e62/script/start.js#L10-L19

Before:

After:

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What is the purpose of this pull request?

• [x] Bug fix
• [ ] New Feature
• [ ] Documentation update
• [ ] Other

Before submitting the PR, please make sure you do the following

• [x] Read the Contributing Guidelines.
• [x] Read the Pull Request Guidelines and follow the Commit Convention.
• [x] Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).