[damonbayer]

Refs #2657.

Changes

• Register the historical log export task once during application launch.
• Check export manager readiness on the main queue and run the export on a background queue. Complete the task with a failure if the export cannot start.

Verification

Swift parsing, plist validation, and git diff --check passed. Xcode rejected the workspace before compilation in the local build attempt. The locked-device launch path still needs device verification.

[ps2]

Thanks, Damon. I checked both paths where the old code could register again: launch() runs from scene(_:willConnectTo:) and again from applicationProtectedDataDidBecomeAvailable when launch was deferred on a locked device. The second call registered the same identifier after launch had finished, and BGTaskScheduler aborts on that. Registering once in didFinishLaunching fixes it. Running the handler on main, so it reads criticalEventLogExportManager on the queue that sets it, and completing the task on failure are both improvements. It builds cleanly with the LoopWorkspace scheme.

One possible follow-up, separate from this PR: when iOS launches Loop in the background only for this task, no scene connects (or protected data isn't available), so the export manager is nil and the task now fails right away. Nothing reschedules it until the next full launch calls scheduleCriticalEventLogHistoricalExportBackgroundTask(). That was already the case before this change.