Auto relaunch in startup update

[iamnoksio]

Greptile Summary

This PR adds automatic relaunch behavior to the startup update check: when autoUpdate is enabled and an update is found on launch, the app now downloads, installs, and immediately relaunches into the new binary rather than deferring to the next manual launch. The accompanying comment on checkOnStartup is updated to reflect this.

• The relaunch is correctly gated behind get().status === "ready", so non-release builds (where downloadInstall short-circuits to status: "available") and failed downloads are safe.
• The relaunch error is handled in its own try/catch with a user-friendly message distinct from the outer "Failed to check for updates" catch, addressing a concern from a previous review.
• Formatting-only changes (brace style, line wrapping) make up the rest of the diff.

Confidence Score: 5/5

Safe to merge — the change is narrowly scoped to the startup path and the relaunch is properly guarded and error-handled.

The relaunch is gated on get().status === 'ready', which prevents premature restarts on non-release builds or failed downloads. The relaunch error path produces a user-facing message distinct from the outer download/check error. No existing behavior outside checkOnStartup is affected.

Files Needing Attention: No files require special attention.

Important Files Changed

Filename	Overview
src/stores/updater-store.ts	Adds auto-relaunch after silent startup install; relaunch is correctly gated on status === 'ready' and wrapped in its own try/catch with an accurate error message. The rest of the diff is cosmetic reformatting.

_{Reviews (3): Last reviewed commit: "fix(updater): report relaunch failures a..." | Re-trigger Greptile}