Fix crash due to prematurely pruned statuses being fetched

If the app hasn't launched in long enough, we may be displaying old statuses as a result of state restoration. If the user leaves the app, those statuses can't get pruned, because the user may return. We need to make sure the lastFetchedAt date is current, since awakeFromFetch won't be called until the object is faulted in (which wasn't happening immediately during state restoration).

Tusker/CoreData/AccountMO.swift

@@ -59,10 +59,15 @@ public final class AccountMO: NSManagedObject, AccountProtocol {
         super.awakeFromFetch()
         
         managedObjectContext?.perform {
-            self.lastFetchedAt = Date()
+            self.touch()
         }
     }
     
+    /// Update the `lastFetchedAt` date so this object isn't pruned early.
+    func touch() {
+        lastFetchedAt = Date()
+    }
+
 }
 
 extension AccountMO {

Tusker/CoreData/StatusMO.swift

@@ -89,10 +89,15 @@ public final class StatusMO: NSManagedObject, StatusProtocol {
         super.awakeFromFetch()
         
         managedObjectContext?.perform {
-            self.lastFetchedAt = Date()
+            self.touch()
         }
     }
     
+    /// Update the `lastFetchedAt` date so this object isn't pruned early.
+    func touch() {
+        lastFetchedAt = Date()
+    }
+    
 }
 
 extension StatusMO {

Tusker/Screens/Timeline/TimelineViewController.swift

@@ -440,7 +440,15 @@ class TimelineViewController: UIViewController, TimelineLikeCollectionViewContro
     private func loadStatusesToRestore(position: TimelinePosition) async -> Bool {
         let originalPositionStatusIDs = position.statusIDs
         
-        let unloaded = position.statusIDs.filter({ mastodonController.persistentContainer.status(for: $0) == nil })
+        var unloaded = [String]()
+        for id in position.statusIDs {
+            if let status = mastodonController.persistentContainer.status(for: id) {
+                // touch the status so that, even if it's old, it doesn't get pruned when we go into the background
+                status.touch()
+            } else {
+                unloaded.append(id)
+            }
+        }
         guard !unloaded.isEmpty else {
             return true
         }