chore(apple): add screenshot studio

apple/VniDrop/App/ScreenshotSupport.swift

@@ -0,0 +1,109 @@
+#if DEBUG
+import Foundation
+import Combine
+import VnidropCore
+
+/// Which marketing screen to stage. Selected via the `-VniScreenshot <name>` launch
+/// argument (read from `NSArgumentDomain`), set by the App Store screenshot UI test.
+enum ScreenshotScenario: String {
+	case transferDetails = "transfer-details" // Send Anywhere: the detail view
+	case share                                 // Share Securely: the QR / share panel
+	case approval                              // Choose Receivers: the receive-request modal
+
+	/// The active scenario for this launch, or `nil` in a normal run.
+	static var current: ScreenshotScenario? {
+		guard let raw = UserDefaults.standard.string(forKey: "VniScreenshot") else { return nil }
+		return ScreenshotScenario(rawValue: raw)
+	}
+}
+
+/// A fixture `CoreGateway` that publishes deterministic content instead of driving
+/// the Rust core, so App Store screenshots are stable and localized. Only the reads
+/// the screenshot screens need are meaningful; mutations are inert.
+@MainActor
+final class ScreenshotCoreGateway: CoreGateway {
+	private let scenario: ScreenshotScenario
+	private let subject: CurrentValueSubject<CoreState, Never>
+	private let signalSubject = PassthroughSubject<CoreSignal, Never>()
+
+	/// Deterministic fixture transfer shown across every scenario.
+	static let transferId: UInt64 = 1
+	private let fixtureTransfer = Transfer(
+		localId: "screenshot-1",
+		transferId: ScreenshotCoreGateway.transferId,
+		direction: .send,
+		status: .sharing,
+		peerId: nil,
+		transferName: "Transfer.MOV",
+		contentHash: "b1946ac92492d2347c6235b4d2611184",
+		fileCount: 1,
+		totalSize: 9_100_000,
+		ticket: "vnd://screenshot-demo-ticket-abcdefghijklmnopqrstuvwxyz0123456789",
+		accessPolicy: .requireApproval,
+		createdAt: 1_722_000_000,
+		updatedAt: 1_722_000_000
+	)
+
+	init(scenario: ScreenshotScenario) {
+		self.scenario = scenario
+		self.subject = CurrentValueSubject(CoreState())
+	}
+
+	var state: CoreState { subject.value }
+	var statePublisher: AnyPublisher<CoreState, Never> { subject.eraseToAnyPublisher() }
+	var signals: AnyPublisher<CoreSignal, Never> { signalSubject.eraseToAnyPublisher() }
+
+	func initialize(appDataDir: String, networkConfiguration: RelayConfiguration) async -> Result<Void, Error> {
+		subject.value = CoreState(
+			isInitialized: true,
+			status: CoreStatus(endpointId: "screenshot-endpoint", activeTransfers: 1, activeShares: 1),
+			events: [],
+			transfers: [fixtureTransfer],
+			lastShare: nil,
+			lastInspection: nil
+		)
+		// Nudge the approval coordinator to (re)read requests for the sharing transfer.
+		signalSubject.send(.approvalChanged(transferId: Self.transferId))
+		return .success(())
+	}
+
+	func receiverRequests(transferId: UInt64) async -> Result<[ReceiverRequestModel], Error> {
+		guard scenario == .approval else { return .success([]) }
+		return .success([
+			ReceiverRequestModel(
+				id: "screenshot-request-1",
+				transferId: Self.transferId,
+				remoteEndpointId: "k51qzi5uqu5d-screenshot-peer-endpoint-identity",
+				transferName: "Transfer.MOV",
+				receiverName: nil,
+				receiverDeviceName: "Mac mini",
+				appVersion: "1.0",
+				status: .requested,
+				reason: nil,
+				requestedAt: 1_722_000_000,
+				respondedAt: nil,
+				completedAt: nil
+			)
+		])
+	}
+
+	// MARK: - Inert mutations (screenshots never exercise these)
+
+	func shutdown() {}
+	func shareSources(_ sources: [ShareSource], transferName: String, senderName: String, accessPolicy: ShareAccessPolicy) async -> Result<Share, Error> {
+		.failure(ScreenshotGatewayError.unsupported)
+	}
+	func inspectTicket(_ ticket: String) async -> Result<TicketInspectionModel, Error> { .failure(ScreenshotGatewayError.unsupported) }
+	func receive(ticket: String, outputDir: String, receiverName: String) async -> Result<Void, Error> { .success(()) }
+	func receiveIntoSecurityScopedDirectory(ticket: String, outputDirectoryUrl: String, receiverName: String) async -> Result<Void, Error> { .success(()) }
+	func cancel(transferId: UInt64) async -> Result<Void, Error> { .success(()) }
+	func delete(transferId: UInt64) async -> Result<Void, Error> { .success(()) }
+	func clearReceiveHistory() async -> Result<UInt64, Error> { .success(0) }
+	func storageUsage() async -> Result<CoreStorageUsageModel, Error> { .success(CoreStorageUsageModel(blobStoreBytes: 0, appDataBytes: 0)) }
+	func receivedArtifacts() async -> Result<[ReceivedArtifactModel], Error> { .success([]) }
+	func respondReceiverRequest(requestId: String, accepted: Bool, reason: String?) async -> Result<Void, Error> { .success(()) }
+	func refresh() async -> Result<Void, Error> { .success(()) }
+}
+
+private enum ScreenshotGatewayError: Error { case unsupported }
+#endif