feat(android): implement snackbar overlay behavior

pedi-foods/Sources/PediFoods/State/SnackbarCenter.swift

@@ -1,11 +1,16 @@
 import Foundation
 import SwiftUI
 
+extension Notification.Name {
+    static let snackbarDidChange = Notification.Name("snackbarDidChange")
+}
+
 #if os(Android)
 @MainActor
 final class SnackbarCenter {
     static let shared = SnackbarCenter()
     var current: SnackbarMessage?
+    private var dismissTask: Task<Void, Never>?
 
     func show(
         title: String,
@@ -14,11 +19,40 @@ final class SnackbarCenter {
         duration: TimeInterval = 3.5,
         action: (() -> Void)? = nil
     ) {
+        dismissTask?.cancel()
+        current = SnackbarMessage(
+            title: title,
+            style: style,
+            iconSystemName: icon,
+            duration: duration,
+            action: action
+        )
+        notifyChange()
+
+        dismissTask = Task { [weak self] in
+            let nanos = UInt64(max(0.2, duration) * 1_000_000_000)
+            try? await Task.sleep(nanoseconds: nanos)
+            guard !Task.isCancelled else { return }
+            self?.dismiss(animated: true)
+        }
+    }
+
+    func handleTap() {
+        let action = current?.action
+        dismiss(animated: true)
         action?()
     }
 
-    func handleTap() {}
-    func dismiss(animated: Bool) {}
+    func dismiss(animated: Bool) {
+        dismissTask?.cancel()
+        dismissTask = nil
+        current = nil
+        notifyChange()
+    }
+
+    private func notifyChange() {
+        NotificationCenter.default.post(name: .snackbarDidChange, object: nil)
+    }
 }
 #else
 @MainActor