Handle runtime auto-update interval changes and UI-thread OCR toasts

[Copilot]

Update notifications were only evaluated against the auto-update interval captured at service startup, so changing the interval to Never did not stop the periodic loop until the original timer elapsed. The PR also addresses the cross-thread OCR toast dismissal path that could crash the WPF test host.

• Auto-update scheduling

  • Replace the single long PeriodicTimer wait with a settings-aware wait loop that re-reads AutoUpdateCheckInterval while waiting.
  • Stop the loop promptly when the interval becomes Never.
  • Recompute the next wait when the interval changes at runtime instead of waiting out the stale schedule.

• Regression coverage

  • Replace the timing-dependent test with deterministic coverage that waits for the hosted service task to complete after switching the setting to Never.
  • Keep the assertion focused on the intended contract: one startup check, no further periodic checks.

• WPF dispatcher safety

  • Marshal OCR toast display/dismissal back to the window dispatcher.
  • Guard toast updates during shutdown so delayed UI work does not touch dispatcher-owned controls after teardown.

while (!stoppingToken.IsCancellationRequested)
{
    var interval = _userSettings.Current.AutoUpdateCheckInterval;
    if (interval == UpdateCheckInterval.Never)
    {
        return false;
    }

    var remaining = GetTimerInterval(interval);
    while (remaining > TimeSpan.Zero)
    {
        var delay = TimeSpan.FromTicks(Math.Min(remaining.Ticks, _settingsPollInterval.Ticks));
        await Task.Delay(delay, stoppingToken);

        var currentInterval = _userSettings.Current.AutoUpdateCheckInterval;
        if (currentInterval == UpdateCheckInterval.Never) return false;
        if (currentInterval != interval) break;

        remaining -= delay;
    }

    if (remaining <= TimeSpan.Zero) return true;
}

[Copilot]

Pull request overview

This PR improves runtime correctness and test reliability by making auto-update scheduling responsive to live settings changes, and by ensuring OCR toast UI updates are marshaled safely to the WPF UI thread (including during shutdown).

Changes:

• Replace the long PeriodicTimer wait with a settings-aware wait loop that re-reads AutoUpdateCheckInterval and stops promptly when set to Never.
• Update auto-update tests to deterministically verify the periodic loop terminates after switching the interval to Never.
• Marshal OCR toast show/hide work to the window dispatcher and add shutdown guards to avoid cross-thread/access-after-teardown crashes.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
Pointframe/Views/OverlayWindow.xaml.cs	Adds dispatcher marshalling and shutdown guards for OCR toast display/dismissal.
Pointframe/Services/Update/AutoUpdateService.cs	Reworks periodic scheduling to react to runtime interval changes via a poll-based wait loop.
Pointframe.Tests/Services/AutoUpdateServiceTests.cs	Replaces timing-dependent coverage with a deterministic “stop promptly after switching to Never” test.

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