Feature Settings Module

@MainActor
@Observable
public final class SettingsViewModel {
    public var theme: SettingsDTO.Theme
    public var shareDiagnostics: Bool
    public var notificationsEnabled: Bool
    public var hapticsEnabled: Bool
    public var reduceMotion: Bool
    public var isSubscribed: Bool

    public func setTheme(_ newTheme: SettingsDTO.Theme) async
    public func toggleDiagnostics(_ enabled: Bool) async
    public func signOut() async
}

@MainActor
@Observable
public final class PaywallViewModel {
    public var offerings: [PaymentsOffering]
    public var selectedOffering: PaymentsOffering?
    public var isLoading: Bool
    public var errorMessage: String?
    public var isSubscribed: Bool

    public func selectOffering(_ offering: PaymentsOffering)
    public func purchase() async
    public func restore() async
}

// 1. Add the field to the persisted SwiftData model (theme is stored as a String)
@Model
public final class Settings {
    public var theme: String
    public var shareDiagnostics: Bool
    public var autoSaveChats: Bool = true  // New setting
}

// 2. Add it to the SettingsDTO so the repository can load/save it
public struct SettingsDTO: Sendable, Equatable {
    public let autoSaveChats: Bool  // New setting
}

// 3. Add to ViewModel and persist via the repository's save(_:)
@Observable
public final class SettingsViewModel {
    public var autoSaveChats: Bool = true

    public func toggleAutoSave(_ enabled: Bool) async {
        autoSaveChats = enabled
        // load the current DTO, set the new value, then save the updated copy
    }
}

// 4. Add to UI
Toggle("Auto-save Chats", isOn: $viewModel.autoSaveChats)
    .onChange(of: viewModel.autoSaveChats) {
        Task { await viewModel.toggleAutoSave($0) }
    }

// In PaywallView, edit the feature list — each row is a FeatureRow
// (FeatureRow lives in PaywallView+Components.swift):
FeatureRow(icon: "sparkles", title: "Advanced AI", description: "Get smarter responses with enhanced models")
FeatureRow(icon: "bolt.fill", title: "Faster Processing", description: "Priority queue for quicker results")
FeatureRow(icon: "infinity", title: "Unlimited Usage", description: "No daily limits or restrictions")
FeatureRow(icon: "star.fill", title: "Your Feature", description: "Describe the benefit")  // Add your feature

// 1. Add a color set in Packages/DesignSystem/Sources/DesignSystem/Resources/Assets.xcassets
// 2. Add a case to SettingsDTO.Theme (in the Storage package)
public enum Theme: String, Sendable, Equatable, CaseIterable {
    case system, light, dark, aurora, obsidian
    case custom  // New theme
}

// 3. Map the new case in DSColors / ThemePalette (DesignSystem) and in
//    SettingsDTO.Theme's displayName / symbolName / isPremium helpers
// 4. The Appearance picker is CaseIterable-driven, so it picks up the new case automatically