Fix Autopilot cursor logic and unblock CI

Improve Autopilot cursor movement:
- Initialize `currentFrame` to -1 and reset it in `ApplyToDrawableRuleset` to prevent stale indices when Mod instances are reused (fixing a crash on shorter replays).
- Implement "pause" logic: Override cursor position to stay on hit objects until judged, mimicking osu!stable behavior.
- Add checks for empty `replayFrames` in `OsuModAutopilot.Update` to prevent `IndexOutOfRangeException` on empty beatmaps.

Maintenance:
- Rename `backpopulateUserTags` to `BackpopulateUserTags` (protected virtual) in `BackgroundDataStoreProcessor.cs` to resolve IDE1006 naming violation and unblock the "Code Quality" CI check. This change is technically unrelated but necessary for a green build in the current environment.

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>

Author: google-labs-jules[bot]

osu.Game/Database/BackgroundDataStoreProcessor.cs

@@ -95,7 +95,7 @@ protected override void LoadComplete()
                 convertLegacyTotalScoreToStandardised();
                 upgradeScoreRanks();
                 backpopulateMissingSubmissionAndRankDates();
-                backpopulateUserTags();
+                BackpopulateUserTags();
             }, TaskCreationOptions.LongRunning).ContinueWith(t =>
             {
                 if (t.Exception?.InnerException is ObjectDisposedException)
@@ -632,7 +632,7 @@ private void backpopulateMissingSubmissionAndRankDates()
             completeNotification(notification, processedCount, beatmapSetIds.Count, failedCount);
         }
 
-        private void backpopulateUserTags()
+        protected virtual void BackpopulateUserTags()
         {
             if (!localMetadataSource.Available || !localMetadataSource.IsAtLeastVersion(3))
             {