WIP: date pills начало + memory: no MVP policy

Rosetta/Features/Chats/ChatDetail/ListView/RosettaMessageListController.swift

@@ -56,6 +56,11 @@ final class RosettaMessageListController: UIViewController {
 
     private let listView = RosettaListView(frame: .zero)
 
+    /// Floating date pill overlay (Telegram-style sticky date headers).
+    private let datePillOverlay = UIView()
+    private var datePillPool: [(container: UIView, label: UILabel)] = []
+    var topStickyOffset: CGFloat = 0
+
     // MARK: - State
 
     private var messages: [ChatMessage] = []
@@ -99,7 +104,20 @@ final class RosettaMessageListController: UIViewController {
             }
         }
         listView.onScroll = { [weak self] _, _ in
-            // TODO: scroll-to-bottom button visibility
+            self?.updateFloatingDatePills()
+        }
+
+        // Date pill overlay
+        datePillOverlay.frame = view.bounds
+        datePillOverlay.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+        datePillOverlay.isUserInteractionEnabled = false
+        view.addSubview(datePillOverlay)
+
+        // Pre-create date pill pool (reuse like NativeMessageList)
+        for _ in 0..<5 {
+            let pill = makeDatePill()
+            datePillOverlay.addSubview(pill.container)
+            datePillPool.append(pill)
         }
 
         // Keyboard tracking