Fix reading-safety and accessibility majors from review

- Transcript: drag suspends auto-follow; long-press selection suspends
  following; Latest is a trailing outlined capsule that re-enables follow
- Lightwell: pulse via isolated TimelineView (2.4s triangle wave), pauses
  when offscreen; Reduce Motion uses static geometry (no level resizing)
- Increase Contrast: solid Rosewood lightwell fill, 2pt Rosewood selected
  outlines on mode buttons
- Haptics: success only on entering ready, error only on entering failure

Sources/Features/Conversation/LightwellView.swift

@@ -26,9 +26,6 @@ struct LightwellView: View {
     /// Compact (24×36) in the conversation status strip; full (64×96) on welcome.
     var compact: Bool = false
     @Environment(\.accessibilityReduceMotion) private var reduceMotion
-    /// Pending-state pulse driver, 0 → 1 → 0 over the 2.4s cycle.
-    @State private var pulse: Double = 0
-
     /// Frame dimensions never animate; inner dimensions multiply by 0.375
     /// in the compact frame.
     private var frameSize: CGSize {
@@ -41,55 +38,87 @@ struct LightwellView: View {
             : base
     }
 
+    @Environment(\.colorSchemeContrast) private var contrast
+
     var body: some View {
-        let inner = innerSize
-        ZStack {
-            Capsule()
-                .fill(Nearlight.surface)
-            Capsule()
-                .fill(
-                    LinearGradient(
-                        stops: [
-                            .init(color: Nearlight.rosewood.opacity(0.35), location: 0),
-                            .init(color: Nearlight.rosewood.opacity(1), location: 0.5),
-                            .init(color: Nearlight.rosewood.opacity(0.55), location: 1),
-                        ],
-                        startPoint: .top, endPoint: .bottom
-                    )
-                )
-                .frame(width: inner.width, height: inner.height)
-                .opacity(overallOpacity)
-                .animation(reduceMotion ? nil : Nearlight.quick, value: overallOpacity)
-                .animation(reduceMotion ? nil : Nearlight.settle, value: innerSize)
-        }
-        .frame(width: frameSize.width, height: frameSize.height)
-        .overlay(
-            Capsule().strokeBorder(Nearlight.quiet, lineWidth: 1)
-        )
-        .accessibilityHidden(true)
-        .task(id: pulseActive) {
-            guard pulseActive else {
-                pulse = 0
-                return
-            }
-            while !Task.isCancelled {
-                withAnimation(reduceMotion ? nil : Nearlight.cycle) { pulse = pulse == 0 ? 1 : 0 }
-                try? await Task.sleep(for: .seconds(2.4))
+        Group {
+            if pulseWanted {
+                // Isolated TimelineView: ticks only while pending states are
+                // showing; pauses when offscreen/inactive automatically.
+                TimelineView(.periodic(from: .now, by: 0.05)) { context in
+                    lightwell(pulse: pulseValue(at: context.date))
+                }
+            } else {
+                lightwell(pulse: 0)
             }
         }
     }
 
-    /// Whether the pulse loop should run for this phase.
-    private var pulseActive: Bool {
+    private func lightwell(pulse: Double) -> some View {
+        let inner = innerSize
+        return ZStack {
+            Capsule()
+                .fill(Nearlight.surface)
+            Capsule()
+                .fill(innerFill)
+                .frame(width: inner.width, height: inner.height)
+                .opacity(overallOpacity(pulse: pulse))
+        }
+        .frame(width: frameSize.width, height: frameSize.height)
+        .overlay(
+            Capsule().strokeBorder(
+                contrast == .increased ? Nearlight.rosewood : Nearlight.quiet,
+                lineWidth: 1
+            )
+        )
+        .accessibilityHidden(true)
+        .animation(reduceMotion ? nil : Nearlight.settle, value: innerSize)
+    }
+
+    /// Increase Contrast promotes the gradient to solid Rosewood.
+    private var innerFill: AnyShapeStyle {
+        if contrast == .increased {
+            return AnyShapeStyle(Nearlight.rosewood)
+        }
+        return AnyShapeStyle(
+            LinearGradient(
+                stops: [
+                    .init(color: Nearlight.rosewood.opacity(0.35), location: 0),
+                    .init(color: Nearlight.rosewood.opacity(1), location: 0.5),
+                    .init(color: Nearlight.rosewood.opacity(0.55), location: 1),
+                ],
+                startPoint: .top, endPoint: .bottom
+            )
+        )
+    }
+
+    /// Whether a pulse TimelineView should run for this phase.
+    private var pulseWanted: Bool {
         switch phase {
         case .connecting, .waiting, .thinking: return !reduceMotion
         default: return false
         }
     }
 
+    /// Triangle wave 0→1→0 over the 2.4s cycle from the timeline date.
+    private func pulseValue(at date: Date) -> Double {
+        let t = date.timeIntervalSinceReferenceDate.truncatingRemainder(dividingBy: 2.4) / 2.4
+        return t < 0.5 ? t * 2 : (1 - t) * 2
+    }
+
     /// Inner capsule geometry per spec table. `a` is the smoothed level.
+    /// Reduce Motion: static 16×40 (idle/listening) and 16×48 (pending/
+    /// thinking/speaking) with no level-driven resizing.
     private var innerSize: CGSize {
         let base = baseInner
+        if reduceMotion {
+            switch phase {
+            case .waiting, .thinking, .speaking:
+                return CGSize(width: base.width, height: base.height + (compact ? 3 : 8))
+            default:
+                return base
+            }
+        }
         switch phase {
         case .listening(let a):
             let level = min(max(a, 0), 1)
@@ -107,7 +136,7 @@ struct LightwellView: View {
         }
     }
 
-    private var overallOpacity: Double {
+    private func overallOpacity(pulse: Double) -> Double {
         switch phase {
         case .connecting, .waiting:
             return 0.45 + 0.45 * pulse