Full App Store screenshot set via a DEBUG demo harness

    func start() async {

        await load()

        #if DEBUG

        if AppModel.isUITestSeed && podcasts.isEmpty {

            await seedDemoData()

            await load()

        }

        #endif

        await loadQueue()

        await downloads.loadPersisted()

    }

    /// Launch argument `-uiScreen <name>` used by the screenshot harness to open

    /// a specific screen. Always `nil` in Release.

    static var uiDemoScreen: String? {

        #if DEBUG

        let args = ProcessInfo.processInfo.arguments

        if let i = args.firstIndex(of: "-uiScreen"), i + 1 < args.count { return args[i + 1] }

        #endif

        return nil

    }

    #if DEBUG

    static var isUITestSeed: Bool { ProcessInfo.processInfo.arguments.contains("-uiSeed") }

    /// Seeds a demo subscription with episodes, a queue and a resume point, for

    /// generating App Store screenshots. Never compiled into Release.

    private func seedDemoData() async {

        let artwork = URL(string: "https://is1-ssl.mzstatic.com/image/thumb/Podcasts211/v4/47/93/f2/4793f27b-a446-bddc-8ecd-412897249e20/mza_4377126082050666835.jpg/600x600bb.jpg")

        let podcast = Podcast(

            feedURL: URL(string: "https://feeds.audiomeans.fr/feed/64ee3763-1a46-44c2-8640-3a69405a3ad8.xml")!,

            title: "Le Collimateur",

            author: "Alexandre Jubelin / Binge Audio",

            summary: "Le podcast consacré aux questions militaires et stratégiques : entretiens, récits d'opérations et analyses de l'actualité de la défense.",

            imageURL: artwork,

            language: "fr"

        )

        let titles = [

            "Algérie-Maroc, le conflit sans fin",

            "Soldate de l'image. Germaine Kanova",

            "Campagne ukrainienne et SCAF de fin",

            "Chasseurs de Shahed",

            "2 Gaulle 2 Furious",

            "Renseignement : la montée en puissance allemande",

            "Un bilan de la guerre contre l'Iran",

            "Dans le viseur : opérations spéciales",

        ]

        let base = 1_750_000_000.0

        let episodes = titles.enumerated().map { i, title in

            Episode(

                guid: "demo-\(i)",

                title: title,

                summary: "Épisode de démonstration.",

                publicationDate: Date(timeIntervalSince1970: base - Double(i) * 172_800),

                enclosureURL: URL(string: "https://feeds.audiomeans.fr/demo/\(i).mp3"),

                duration: Double(3600 + i * 420),

                imageURL: artwork

            )

        }

        guard let stored = try? await store.save(podcast: podcast, episodes: episodes) else { return }

        let saved = (try? await store.episodes(forPodcastID: stored.id)) ?? []

        for index in [1, 2, 3] where saved.count > index {

            await enqueue(saved[index])

        }

        if let first = saved.first {

            try? await store.setPlayState(

                episodeID: first.id, position: (first.duration ?? 0) * 0.32, isPlayed: false

            )

        }

    }

    #endif

    // MARK: Library

    func load() async {

import SwiftUI

import UniformTypeIdentifiers

import PodcastModel

import PlaybackKit

/// Adaptive root: a sidebar (queue + subscriptions) with a detail pane on

/// iPad/macOS, automatically collapsing to a navigation stack on iPhone.

    @State private var showingOPMLImporter = false

    @State private var importMessage: String?

    #if DEBUG

    @Environment(PlaybackController.self) private var demoPlayback

    @State private var showDemoPlayer = false

    #endif

    private static let opmlTypes: [UTType] = [UTType(filenameExtension: "opml") ?? .xml, .xml]

    enum Destination: Hashable {

        } message: {

            Text(importMessage ?? "")

        }

        .task { await applyDemoScreen() }

        #if DEBUG

        .sheet(isPresented: $showDemoPlayer) {

            PlayerView().environment(demoPlayback)

        }

        #endif

    }

    /// Screenshot harness: opens the screen named by `-uiScreen` once data is

    /// loaded. No-op in Release.

    private func applyDemoScreen() async {

        #if DEBUG

        guard let screen = AppModel.uiDemoScreen else { return }

        for _ in 0..<60 where model.podcasts.isEmpty {

            try? await Task.sleep(for: .milliseconds(100))

        }

        switch screen {

        case "queue": selection = .queue

        case "sync": selection = .sync

        case "detail", "player": selection = model.podcasts.first.map { Destination.podcast($0.id) }

        default: selection = nil

        }

        if screen == "player", let first = model.podcasts.first {

            let episodes = await model.episodes(for: first)

            if let episode = episodes.first { await model.play(episode) }

            try? await Task.sleep(for: .milliseconds(500))

            showDemoPlayer = true

        }

        #endif

    }

    private var importAlertBinding: Binding<Bool> {