feat: Phase 1 auto-scroll engine for Reader feed

ENGINE (ScrollViewDriver.swift):
- UIViewRepresentable placed inside ScrollView (zero size)
- Finds parent UIScrollView via view hierarchy traversal
- CADisplayLink at 60fps drives contentOffset.y smoothly
- Speed: 1.0x = 60pt/sec, adjustable 0.25x–3.0x in 0.25 steps
- User touch detection: intercepts UIScrollViewDelegate
  scrollViewWillBeginDragging → stops auto-scroll immediately
- Stops at bottom (contentOffset >= maxOffset)
- Forwards all delegate methods to SwiftUI's original delegate

INTEGRATION (EntryListView):
- Accepts @Binding isAutoScrolling + scrollSpeed
- ScrollViewDriver placed as first child in ScrollView
- Auto-scroll stops on: user touch, navigation back (onAppear),
  filter change, sub-tab change, reaching bottom

CONTROLS (ReaderTabView — temporary, Phase 1):
- Play/Stop button in toolbar (play.fill / stop.fill)
- When playing: [-] speed [+] controls appear inline
- Speed shown as "1.00x" with monospacedDigit

MARK-AS-READ:
- Auto-scroll drives real UIScrollView contentOffset
- This moves LazyVStack rows, triggering their GeometryReader
  onChange callbacks — the existing mark-as-read system fires
  naturally with no special case or bypass needed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ios/Platform/Platform.xcodeproj/project.pbxproj

@@ -50,6 +50,7 @@
 		A10045 /* ArticleView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B10045 /* ArticleView.swift */; };
 		A10046 /* ArticleWebView.swift in Sources */ = {isa = PBXBuildFile; fileRef = B10046 /* ArticleWebView.swift */; };
 		A10047 /* FeedManagementSheet.swift in Sources */ = {isa = PBXBuildFile; fileRef = B10047 /* FeedManagementSheet.swift */; };
+		A10048 /* ScrollViewDriver.swift in Sources */ = {isa = PBXBuildFile; fileRef = B10048 /* ScrollViewDriver.swift */; };
 		F20549752F805F5800AE8DF5 /* ConfettiSwiftUI in Frameworks */ = {isa = PBXBuildFile; productRef = F20549742F805F5800AE8DF5 /* ConfettiSwiftUI */; };
 /* End PBXBuildFile section */
 
@@ -97,6 +98,7 @@
 		B10045 /* ArticleView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ArticleView.swift; sourceTree = "<group>"; };
 		B10046 /* ArticleWebView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ArticleWebView.swift; sourceTree = "<group>"; };
 		B10047 /* FeedManagementSheet.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedManagementSheet.swift; sourceTree = "<group>"; };
+		B10048 /* ScrollViewDriver.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ScrollViewDriver.swift; sourceTree = "<group>"; };
 		C10001 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		D10001 /* Platform.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Platform.app; sourceTree = BUILT_PRODUCTS_DIR; };
 /* End PBXFileReference section */
@@ -336,6 +338,7 @@
 				B10045 /* ArticleView.swift */,
 				B10046 /* ArticleWebView.swift */,
 				B10047 /* FeedManagementSheet.swift */,
+				B10048 /* ScrollViewDriver.swift */,
 			);
 			path = Views;
 			sourceTree = "<group>";
@@ -454,6 +457,7 @@
 				A10045 /* ArticleView.swift in Sources */,
 				A10046 /* ArticleWebView.swift in Sources */,
 				A10047 /* FeedManagementSheet.swift in Sources */,
+				A10048 /* ScrollViewDriver.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

ios/Platform/Platform/Features/Reader/Views/EntryListView.swift

@@ -3,6 +3,8 @@ import SwiftUI
 struct EntryListView: View {
     @Bindable var vm: ReaderViewModel
     var isCardView: Bool = true
+    @Binding var isAutoScrolling: Bool
+    var scrollSpeed: Double = 1.0
 
     // Scroll-based read tracking — all driven from per-row GeometryReader
     @State private var lastKnownMinY: [Int: CGFloat] = [:]  // entry.id → last minY
@@ -35,6 +37,10 @@ struct EntryListView: View {
             .frame(maxWidth: .infinity, maxHeight: .infinity)
         } else {
             ScrollView {
+                // Auto-scroll engine — zero-size, drives parent UIScrollView
+                ScrollViewDriver(isScrolling: $isAutoScrolling, speed: scrollSpeed)
+                    .frame(width: 0, height: 0)
+
                 if isCardView {
                     cardLayout
                 } else {
@@ -49,6 +55,8 @@ struct EntryListView: View {
                 cumulativeDown = 0
                 cumulativeUp = 0
                 lastKnownMinY.removeAll()
+                // Stop auto-scroll on navigation return
+                isAutoScrolling = false
             }
             .refreshable {
                 await vm.refresh()

ios/Platform/Platform/Features/Reader/Views/ReaderTabView.swift

@@ -6,6 +6,8 @@ struct ReaderTabView: View {
     @State private var showFeedSheet = false
     @State private var showFeedManagement = false
     @State private var isCardView = true
+    @State private var isAutoScrolling = false
+    @State private var scrollSpeed: Double = 1.0
 
     var body: some View {
         NavigationStack {
@@ -83,12 +85,46 @@ struct ReaderTabView: View {
                 .frame(height: 44) // Fixed height prevents layout shift
 
                 // Entry list
-                EntryListView(vm: vm, isCardView: isCardView)
+                EntryListView(vm: vm, isCardView: isCardView, isAutoScrolling: $isAutoScrolling, scrollSpeed: scrollSpeed)
             }
             .frame(maxWidth: .infinity, maxHeight: .infinity)
             .background(Color.canvas)
             .navigationBarHidden(true)
             .toolbar {
+                ToolbarItem(placement: .topBarTrailing) {
+                    // Auto-scroll controls
+                    HStack(spacing: 8) {
+                        if isAutoScrolling {
+                            Button {
+                                scrollSpeed = max(0.25, scrollSpeed - 0.25)
+                            } label: {
+                                Image(systemName: "minus")
+                                    .font(.caption2.weight(.bold))
+                                    .foregroundStyle(Color.accentWarm)
+                            }
+
+                            Text(String(format: "%.2fx", scrollSpeed))
+                                .font(.caption.weight(.semibold).monospacedDigit())
+                                .foregroundStyle(Color.textPrimary)
+                                .frame(width: 42)
+
+                            Button {
+                                scrollSpeed = min(3.0, scrollSpeed + 0.25)
+                            } label: {
+                                Image(systemName: "plus")
+                                    .font(.caption2.weight(.bold))
+                                    .foregroundStyle(Color.accentWarm)
+                            }
+                        }
+
+                        Button {
+                            isAutoScrolling.toggle()
+                        } label: {
+                            Image(systemName: isAutoScrolling ? "stop.fill" : "play.fill")
+                                .foregroundStyle(isAutoScrolling ? .red : Color.accentWarm)
+                        }
+                    }
+                }
                 ToolbarItem(placement: .topBarTrailing) {
                     Button {
                         withAnimation(.easeInOut(duration: 0.2)) {
@@ -142,6 +178,12 @@ struct ReaderTabView: View {
         .onAppear {
             ArticleRenderer.shared.reWarmIfNeeded()
         }
+        .onChange(of: selectedSubTab) { _, _ in
+            isAutoScrolling = false
+        }
+        .onChange(of: vm.currentFilter) { _, _ in
+            isAutoScrolling = false
+        }
     }
 
     private var subTabs: [String] { ["Unread", "Starred", "All"] }

ios/Platform/Platform/Features/Reader/Views/ScrollViewDriver.swift

@@ -0,0 +1,171 @@
+import SwiftUI
+import UIKit
+
+/// Drives smooth auto-scroll on the parent UIScrollView.
+/// Uses CADisplayLink for 60fps continuous motion.
+/// Detects user touch to stop auto-scroll immediately.
+struct ScrollViewDriver: UIViewRepresentable {
+    @Binding var isScrolling: Bool
+    let speed: Double // 1.0 = 60pt/sec
+
+    func makeUIView(context: Context) -> UIView {
+        let view = DriverView()
+        view.coordinator = context.coordinator
+        view.frame = .zero
+        view.isUserInteractionEnabled = false
+        return view
+    }
+
+    func updateUIView(_ uiView: UIView, context: Context) {
+        guard let driver = uiView as? DriverView else { return }
+        let coordinator = context.coordinator
+        coordinator.speed = speed
+        coordinator.isScrollingBinding = $isScrolling
+
+        if isScrolling && coordinator.displayLink == nil {
+            coordinator.startScrolling(in: driver)
+        } else if !isScrolling && coordinator.displayLink != nil {
+            coordinator.stopScrolling()
+        }
+    }
+
+    func makeCoordinator() -> Coordinator {
+        Coordinator()
+    }
+
+    // MARK: - DriverView
+
+    /// Subclass that finds the parent UIScrollView once added to the hierarchy.
+    class DriverView: UIView {
+        weak var coordinator: Coordinator?
+
+        override func didMoveToWindow() {
+            super.didMoveToWindow()
+            if window != nil {
+                coordinator?.findScrollView(from: self)
+            }
+        }
+    }
+
+    // MARK: - Coordinator
+
+    class Coordinator: NSObject, UIScrollViewDelegate {
+        weak var scrollView: UIScrollView?
+        var displayLink: CADisplayLink?
+        var speed: Double = 1.0
+        var isScrollingBinding: Binding<Bool>?
+        private var originalDelegate: UIScrollViewDelegate?
+        private var delegateInstalled = false
+
+        func findScrollView(from view: UIView) {
+            var current: UIView? = view.superview
+            while let v = current {
+                if let sv = v as? UIScrollView {
+                    scrollView = sv
+                    installDelegate(on: sv)
+                    return
+                }
+                current = v.superview
+            }
+        }
+
+        private func installDelegate(on scrollView: UIScrollView) {
+            guard !delegateInstalled else { return }
+            delegateInstalled = true
+            // Store original delegate (SwiftUI's) and intercept
+            originalDelegate = scrollView.delegate
+            scrollView.delegate = self
+        }
+
+        func startScrolling(in view: UIView) {
+            // Re-find scroll view if needed
+            if scrollView == nil {
+                findScrollView(from: view)
+            }
+            guard scrollView != nil else { return }
+
+            let link = CADisplayLink(target: self, selector: #selector(tick))
+            link.preferredFrameRateRange = CAFrameRateRange(minimum: 30, maximum: 60)
+            link.add(to: .main, forMode: .common)
+            displayLink = link
+        }
+
+        func stopScrolling() {
+            displayLink?.invalidate()
+            displayLink = nil
+        }
+
+        @objc private func tick(_ link: CADisplayLink) {
+            guard let sv = scrollView else {
+                stopAndNotify()
+                return
+            }
+
+            let maxOffset = sv.contentSize.height - sv.bounds.height + sv.contentInset.bottom
+            guard maxOffset > 0 else { return }
+
+            // 60pt/sec at 1.0x speed, scaled by actual frame duration
+            let delta = CGFloat(speed) * 60.0 * CGFloat(link.targetTimestamp - link.timestamp)
+            let newY = min(sv.contentOffset.y + delta, maxOffset)
+
+            sv.contentOffset.y = newY
+
+            // Stop at bottom
+            if newY >= maxOffset - 1 {
+                stopAndNotify()
+            }
+        }
+
+        private func stopAndNotify() {
+            stopScrolling()
+            DispatchQueue.main.async { [weak self] in
+                self?.isScrollingBinding?.wrappedValue = false
+            }
+        }
+
+        // MARK: - UIScrollViewDelegate (intercept user touch)
+
+        func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
+            // User touched the scroll view — stop auto-scroll
+            if displayLink != nil {
+                stopAndNotify()
+            }
+            // Forward to original delegate
+            originalDelegate?.scrollViewWillBeginDragging?(scrollView)
+        }
+
+        // Forward all other delegate methods to original
+
+        func scrollViewDidScroll(_ scrollView: UIScrollView) {
+            originalDelegate?.scrollViewDidScroll?(scrollView)
+        }
+
+        func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
+            originalDelegate?.scrollViewDidEndDragging?(scrollView, willDecelerate: decelerate)
+        }
+
+        func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
+            originalDelegate?.scrollViewDidEndDecelerating?(scrollView)
+        }
+
+        func scrollViewShouldScrollToTop(_ scrollView: UIScrollView) -> Bool {
+            originalDelegate?.scrollViewShouldScrollToTop?(scrollView) ?? true
+        }
+
+        func scrollViewDidScrollToTop(_ scrollView: UIScrollView) {
+            originalDelegate?.scrollViewDidScrollToTop?(scrollView)
+        }
+
+        func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
+            originalDelegate?.scrollViewWillEndDragging?(scrollView, withVelocity: velocity, targetContentOffset: targetContentOffset)
+        }
+
+        deinit {
+            displayLink?.invalidate()
+            // Restore original delegate
+            if let sv = scrollView, delegateInstalled {
+                sv.delegate = originalDelegate
+            }
+        }
+    }
+}