feat: enhance models and services with Sendable conformance, add preview data for debugging

Mayday/ViewModels/SettingsViewModel.swift

@@ -11,6 +11,12 @@ class SettingsViewModel: ObservableObject {
     private let service = NotificationsAPIService.shared
 
     func loadSessions() async {
+        #if DEBUG
+        if PreviewData.isPreviewMode {
+            sessions = PreviewData.mockSessions
+            return
+        }
+        #endif
         isLoading = true
         defer { isLoading = false }
         do {
@@ -21,6 +27,12 @@ class SettingsViewModel: ObservableObject {
     }
 
     func deleteSession(_ session: SessionResponse) async {
+        #if DEBUG
+        if PreviewData.isPreviewMode {
+            sessions.removeAll { $0.id == session.id }
+            return
+        }
+        #endif
         do {
             try await service.deleteSession(id: session.id)
             sessions.removeAll { $0.id == session.id }
@@ -30,6 +42,12 @@ class SettingsViewModel: ObservableObject {
     }
 
     func changePassword(current: String, new: String) async -> Bool {
+        #if DEBUG
+        if PreviewData.isPreviewMode {
+            successMessage = "Пароль успешно изменён"
+            return true
+        }
+        #endif
         isLoading = true
         error = nil
         defer { isLoading = false }