fix: ignore tap navigation while user is mid-swipe

KMReader/Features/Reader/Views/NativeCoverPageView_iOS.swift

@@ -111,7 +111,15 @@
         } else if !isAnimatingTransition {
           syncCurrentItemFromViewModel()
           if let navigationTarget = parent.viewModel.navigationTarget {
-            handleNavigationTarget(navigationTarget)
+            // While the user is actively panning, discard tap-initiated navigation.
+            // `isAnimatingTransition` only covers the post-pan commit/cancel animation;
+            // during the pan itself it is false, so an unguarded tap would call
+            // `commitTransition` mid-drag and override the user's gesture.
+            if isUserPanning {
+              parent.viewModel.clearNavigationTarget()
+            } else {
+              handleNavigationTarget(navigationTarget)
+            }
           } else {
             syncSlotContent()
             updateSlotLayout()
@@ -223,6 +231,16 @@
         deckState.currentItem
       }
 
+      private var isUserPanning: Bool {
+        guard let panRecognizer else { return false }
+        switch panRecognizer.state {
+        case .began, .changed:
+          return true
+        default:
+          return false
+        }
+      }
+
       private var pendingTargetItem: ReaderViewItem? {
         guard let transitionDirection else { return nil }
         return transitionDirection == 1 ? deckState.nextItem : deckState.previousItem

KMReader/Features/Reader/Views/NativeCoverPageView_macOS.swift

@@ -112,7 +112,15 @@
         } else if !isAnimatingTransition {
           syncCurrentItemFromViewModel()
           if let navigationTarget = parent.viewModel.navigationTarget {
-            handleNavigationTarget(navigationTarget)
+            // While the user is actively panning, discard tap-initiated navigation.
+            // `isAnimatingTransition` only covers the post-pan commit/cancel animation;
+            // during the pan itself it is false, so an unguarded tap would call
+            // `commitTransition` mid-drag and override the user's gesture.
+            if isUserPanning {
+              parent.viewModel.clearNavigationTarget()
+            } else {
+              handleNavigationTarget(navigationTarget)
+            }
           } else {
             syncSlotContent()
             updateSlotLayout()
@@ -216,6 +224,16 @@
         deckState.currentItem
       }
 
+      private var isUserPanning: Bool {
+        guard let panRecognizer else { return false }
+        switch panRecognizer.state {
+        case .began, .changed:
+          return true
+        default:
+          return false
+        }
+      }
+
       private var pendingTargetItem: ReaderViewItem? {
         guard let transitionDirection else { return nil }
         return transitionDirection == 1 ? deckState.nextItem : deckState.previousItem

KMReader/Features/Reader/Views/ScrollPageView_iOS.swift

@@ -354,6 +354,16 @@
         _ navigationTarget: ReaderViewItem,
         in collectionView: UICollectionView
       ) {
+        // While the user is in the middle of a swipe (drag or its deceleration), ignore
+        // tap-initiated navigation. The drag's intent dominates; layering a programmatic
+        // scroll over natural deceleration produces a double page advance. Mirrors the
+        // existing guard in `scrollViewWillBeginDragging` that lets a drag override an
+        // in-flight programmatic scroll.
+        if engine.isUserInteracting {
+          parent.viewModel.clearNavigationTarget()
+          return
+        }
+
         guard let resolvedTarget = parent.viewModel.resolvedViewItem(for: navigationTarget),
           let targetItem = engine.resolveItem(resolvedTarget)
         else {

KMReader/Features/Reader/Views/ScrollPageView_macOS.swift

@@ -421,6 +421,16 @@
         in scrollView: NSScrollView,
         collectionView: NSCollectionView
       ) {
+        // While the user is in the middle of a swipe (drag or its deceleration), ignore
+        // tap-initiated navigation. The drag's intent dominates; layering a programmatic
+        // scroll over natural deceleration produces a double page advance. Mirrors the
+        // existing guard in `scrollViewWillBeginDragging` that lets a drag override an
+        // in-flight programmatic scroll.
+        if engine.isUserInteracting {
+          parent.viewModel.clearNavigationTarget()
+          return
+        }
+
         guard let resolvedTarget = parent.viewModel.resolvedViewItem(for: navigationTarget),
           let targetItem = engine.resolveItem(resolvedTarget)
         else {