Check Sparkle updates on launch

[yvette-carlisle]

Summary

• request a Sparkle background update check immediately after the updater starts when Auto Update is Notify or Install
• remove the later async launch scheduling path
• shorten the About Auto Update timestamp to Checked <time> so it fits the row

Verification

• cargo make fmt-swift
• cargo make check-swift
• cargo make check-vstyle-swift
• cargo make test-macos-native-host
• scripts/build_and_run.sh --verify