fix: Onboarding persistence and update interval

[littlekirkycode]

Closes #1228
Related: #1229 (skip button addressed in #1240)

Summary

Fixes the root cause of users(or devs) being forced through re-authentication and the onboarding tutorial
after every auto-update.

The problem

logout() in authStore.ts unconditionally reset hasCompletedOnboarding: false. When the app
restarts after an auto-update and token refresh fails (transient network error, brief API
outage), it triggers logout() — which wiped the onboarding flag. The user then sees the full
tutorial again, even though they completed it. With auto-update checks running every
hour, this happened frequently.

Note: The hasCompletedOnboarding reset in logout() was likely added for
development/testing convenience. Issues #1228 and #1230 show this has become a development pain
point, so i've moved the reset to an explicit developer setting instead.

What changed

1. Preserve onboarding state on logout (authStore.ts)

Removed hasCompletedOnboarding: false from the logout() method. Onboarding completion is a
user-level fact — logging out and back in shouldn't force the tutorial again:

 set({
   oauthAccessToken: null,
   isAuthenticated: false,
   hasCodeAccess: null,
-  hasCompletedOnboarding: false,
   selectedPlan: null,
   // ...
 });

2. Add "Reset onboarding" button in Advanced Settings (AdvancedSettings.tsx)

Replaces the implicit logout-based reset with an explicit developer action. Settings → Advanced
→ "Reset onboarding" sets the flag to false, so the tutorial runs on next restart:

<Button
  variant="soft"
  size="1"
  onClick={() => useAuthStore.setState({ hasCompletedOnboarding: false })}
>
  Reset
</Button>

3. Reduce auto-update check interval to 24 hours (updates/service.ts)

- private static readonly CHECK_INTERVAL_MS = 60 * 60 * 1000; // 1 hour
+ private static readonly CHECK_INTERVAL_MS = 24 * 60 * 60 * 1000; // 24 hours

Updated the corresponding test assertions to match.

Changes

File	What
authStore.ts	Remove hasCompletedOnboarding: false from logout()
AdvancedSettings.tsx	Add "Reset onboarding" button for dev testing
updates/service.ts	Change CHECK_INTERVAL_MS from 1h → 24h
updates/service.test.ts	Update test to assert 24h interval

Test plan

• Log in → complete onboarding → log out → log back in → should NOT see onboarding again
• Settings → Advanced → "Reset onboarding" → tutorial re-appears on next restart
• Auto-update check interval is 24h (verify in code or via debug logs)
• pnpm --filter code typecheck passes
• pnpm --filter code test passes

[jonathanlab]

LGTM! We should probably split this onboarding logic up into the tutorial part and a part that is responsible for actually configuring your organization + project settings (e.g. signals/github integration), since that is not a user level concern.