feat: implement quit event

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Description

Closes https://github.com/cinnyapp/cinny-desktop/issues/204 Closes https://github.com/cinnyapp/cinny-desktop/issues/217 Closes https://github.com/cinnyapp/cinny-desktop/issues/351

See also https://github.com/cinnyapp/cinny/pull/1655

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings

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