fix(auto-updater): suppress transient network errors on background polls

[ademczuk]

Summary

Fixes #56. Reporter on Windows is behind a network that cannot resolve the GitHub release feed. The auto-updater polls every hour, every poll fails with net::ERR_NAME_NOT_RESOLVED, every failure fires update-toast:error, and there is no setting to opt out. The same pattern hits anyone on a captive portal, restrictive corporate firewall, or LAN-only network.

Root cause

AutoUpdaterService.setupEventHandlers() at packages/electron/src/main/services/autoUpdater.ts:158-196 fires update-toast:error to the frontmost window for every error event from electron-updater, regardless of:

• the stage (check vs download)
• the cause (network, permission, signature, disk)
• whether the check was user-initiated or the hourly auto-poll

The codebase already has a classifyUpdateError(err) helper at line 33 that returns 'network' | 'permission' | 'disk_space' | 'signature' | 'unknown'. It is currently only used for analytics. This PR uses the same classifier to gate the toast.

Fix

In the existing error handler, capture wasManualCheck before the reset (the existing code resets the flag without remembering its prior value), then suppress update-toast:error when all three are true:

const isTransientNetworkCheckError =
  stage === 'check' && errorType === 'network' && !wasManualCheck;
if (!isTransientNetworkCheckError) {
  this.sendToFrontmostWindow('update-toast:error', { message: err.message });
}

What is preserved exactly as before:

• log.error('Update error:', err) still fires
• AnalyticsService.sendEvent('update_error', ...) still fires with the same shape
• this.sendToAllWindows('update-error', err.message) still fires (any renderer subscriber listening on update-error continues to receive it)
• Manual checks via checkForUpdatesWithUI set isManualCheck = true and still see the toast on failure
• Download errors (any stage that is not 'check') still see the toast
• The Windows EPERM rename retry path at autoUpdater.ts:167 is reached before the toast logic and is unchanged
• The dev-mode-skip toast at line 572 (which emits update-toast:error with a literal "Update checking is not available in development mode") is in a different code path (checkForUpdatesWithUI, manual flow), unchanged

Why not add a hide-update-errors setting

Considered. The reporter explicitly asked "Can the update check be disabled somehow?" - meaning they want to opt out. A setting toggle would address that ask but introduces a real footgun: a user toggling it off would also miss download failures, signature failures, and disk-space failures, which are real problems they should hear about. Suppressing only the transient-network-check class targets the actual pain (recurring noise on a network that cannot reach the feed) without hiding errors that warrant action. Open to adding a setting if you'd prefer that direction.

Class-of-bug check

grep -rn "update-toast:error" packages/electron/src finds three sites:

• autoUpdater.ts:191 - the auto-poll error handler (this PR's site)
• autoUpdater.ts:434 - download retry failure (different stage, intentionally surfaces)
• autoUpdater.ts:572,592 - manual-check-flow errors (intentionally surfaces, user clicked)

Only the first one was the recurring-noise source.

Test plan

• npm run typecheck --workspace=packages/electron passes
• Manual: simulate offline state (disconnect Wi-Fi), let auto-poll fire, no toast appears, debug log still records Update error: ... and analytics still records update_error
• Manual: click Check for Updates while offline, error toast appears (manual check flow preserved)
• Manual: simulate signature failure (e.g. tamper with installer), error toast appears (non-network errors still surface)
• Manual: download error mid-flight, toast appears (download stage still surfaces)

Closes

Fixes #56.

[ademczuk]

Hey @ghinkle, small one for #56. Reuses the existing classifyUpdateError helper so it is a single condition added in the error handler. Manual checks and download errors still surface normally.