feat: auto-scroll speed cycles via tab bar button (Slow/Med/Fast)

Tab bar action button cycles through speeds on each tap:
- ▶ (play) → tap → Slow (1.5x, hare icon)
- Slow → tap → Med (1.75x, walk icon)
- Med → tap → Fast (2.0x, bolt icon)
- Fast → tap → back to Slow

Touch feed to stop → icon returns to ▶

Removed speed controls from Reader toolbar — all speed control
is now in the single tab bar button. Clean, no overlays.

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

ios/Platform/Platform/ContentView.swift

@@ -29,21 +29,41 @@ struct MainTabView: View {
     @State private var confettiTrigger = 0
     @State private var readerVM = ReaderViewModel()
     @State private var isAutoScrolling = false
-    @State private var scrollSpeed: Double = 1.0
+    @State private var scrollSpeed: Double = 1.5
+    @State private var speedLevel = 0  // 0=slow, 1=med, 2=fast
     @State private var previousTab = 0
 
     private var showReader: Bool {
         auth.currentUser?.id != 4
     }
 
-    // Dynamic icon for the search-role tab based on context
+    private let speedLevels: [(String, String, Double)] = [
+        ("Slow", "hare", 1.5),
+        ("Med", "figure.walk", 1.75),
+        ("Fast", "bolt.fill", 2.0),
+    ]
+
+    // Dynamic icon + label for the search-role tab
     private var actionIcon: String {
+        if selectedTab == 2 && isAutoScrolling {
+            return speedLevels[speedLevel].1
+        }
         if selectedTab == 2 {
-            return isAutoScrolling ? "pause.fill" : "play.fill"
+            return "play.fill"
         }
         return "plus"
     }
 
+    private var actionLabel: String {
+        if selectedTab == 2 && isAutoScrolling {
+            return speedLevels[speedLevel].0
+        }
+        if selectedTab == 2 {
+            return "Play"
+        }
+        return "Add"
+    }
+
     var body: some View {
         ZStack {
             TabView(selection: $selectedTab) {
@@ -67,7 +87,7 @@ struct MainTabView: View {
                 Tab(value: 3, role: .search) {
                     Color.clear
                 } label: {
-                    Label("Action", systemImage: actionIcon)
+                    Label(actionLabel, systemImage: actionIcon)
                 }
             }
             .tint(Color.accentWarm)
@@ -119,9 +139,15 @@ struct MainTabView: View {
 
     private func handleActionTap(from sourceTab: Int) {
         if sourceTab == 2 {
-            // Reader: toggle auto-scroll, return to Reader
-            withAnimation(.spring(duration: 0.3)) {
-                isAutoScrolling.toggle()
+            if !isAutoScrolling {
+                // First tap: start at Slow
+                speedLevel = 0
+                scrollSpeed = speedLevels[0].2
+                isAutoScrolling = true
+            } else {
+                // Cycle: Slow → Med → Fast → Slow
+                speedLevel = (speedLevel + 1) % speedLevels.count
+                scrollSpeed = speedLevels[speedLevel].2
             }
             selectedTab = 2
         } else {

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

@@ -24,28 +24,7 @@ struct ReaderTabView: View {
                 .navigationSubtitle(subtitleText)
                 .navigationBarTitleDisplayMode(.inline)
                 .toolbar {
-                    if isAutoScrolling {
-                        // Auto-scroll mode: speed controls in toolbar
-                        ToolbarItemGroup(placement: .topBarLeading) {
-                            Button {
-                                scrollSpeed = max(0.25, scrollSpeed - 0.25)
-                            } label: {
-                                Image(systemName: "minus")
-                            }
-
-                            Text(String(format: "%.2fx", scrollSpeed))
-                                .font(.body.weight(.bold).monospacedDigit())
-                                .foregroundStyle(Color.textPrimary)
-
-                            Button {
-                                scrollSpeed = min(3.0, scrollSpeed + 0.25)
-                            } label: {
-                                Image(systemName: "plus")
-                            }
-                        }
-                    } else {
-                        // Normal mode: controls
-                        ToolbarItemGroup(placement: .topBarTrailing) {
+                    ToolbarItemGroup(placement: .topBarTrailing) {
                             Button {
                                 withAnimation(.easeInOut(duration: 0.2)) {
                                     isCardView.toggle()
@@ -84,8 +63,6 @@ struct ReaderTabView: View {
                                 Image(systemName: "ellipsis")
                             }
                         }
-                    }
-
                 }
                 .sheet(isPresented: $showFeedSheet) {
                     AddFeedSheet(vm: vm)