WP-0: SwiftPM scaffold, shared model, signed app bundle script

Sources/ShotdeckCore/Model/Capture.swift

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+import Foundation
+
+/// One screenshot plus everything needed to place it on a PDF page.
+public struct Capture: Codable, Sendable, Identifiable, Equatable {
+    public let id: UUID
+    /// 1-based position within its session. Stable; never renumbered on delete.
+    public let sequence: Int
+    /// File name only (e.g. "001-A1B2C3D4.png"), never a path.
+    /// The directory is always the owning session's directory.
+    public let fileName: String
+    /// Pixel dimensions of the PNG on disk.
+    public let pixelWidth: Int
+    public let pixelHeight: Int
+    /// Backing scale the capture was taken at (2.0 on Retina). Needed so the PDF
+    /// composer lays the image out at its true point size, not its pixel size.
+    public let scale: CGFloat
+    /// When the screenshot was taken. Always stored as an absolute instant;
+    /// rendered in Asia/Dubai wherever a human sees it.
+    public let capturedAt: Date
+
+    public init(
+        id: UUID,
+        sequence: Int,
+        fileName: String,
+        pixelWidth: Int,
+        pixelHeight: Int,
+        scale: CGFloat,
+        capturedAt: Date
+    ) {
+        self.id = id
+        self.sequence = sequence
+        self.fileName = fileName
+        self.pixelWidth = pixelWidth
+        self.pixelHeight = pixelHeight
+        self.scale = scale
+        self.capturedAt = capturedAt
+    }
+
+    /// True when the image is wider than it is tall. Drives page orientation.
+    public var isLandscape: Bool {
+        pixelWidth > pixelHeight
+    }
+}

Sources/ShotdeckCore/Model/CaptureSession.swift

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+import Foundation
+
+public enum SessionState: String, Codable, Sendable {
+    case open      // accepting captures
+    case archived  // its PDF has been built and sent; kept forever, never deleted
+}
+
+/// The manifest persisted as session.json alongside the PNGs.
+public struct CaptureSession: Codable, Sendable, Identifiable, Equatable {
+    public let id: UUID
+    public let createdAt: Date
+    public private(set) var state: SessionState
+    public private(set) var captures: [Capture]
+    /// Set when the PDF is built, so a re-send reuses the same file.
+    public private(set) var pdfFileName: String?
+
+    public init(
+        id: UUID,
+        createdAt: Date,
+        state: SessionState,
+        captures: [Capture],
+        pdfFileName: String?
+    ) {
+        self.id = id
+        self.createdAt = createdAt
+        self.state = state
+        self.captures = captures
+        self.pdfFileName = pdfFileName
+    }
+
+    public var isEmpty: Bool {
+        captures.isEmpty
+    }
+
+    /// max(sequence)+1, or 1 when empty.
+    public var nextSequence: Int {
+        (captures.map(\.sequence).max() ?? 0) + 1
+    }
+
+    /// Value-semantic: returns a new session; does not mutate `self`.
+    public func appending(_ capture: Capture) -> CaptureSession {
+        CaptureSession(
+            id: id,
+            createdAt: createdAt,
+            state: state,
+            captures: captures + [capture],
+            pdfFileName: pdfFileName
+        )
+    }
+
+    /// Value-semantic: returns a new session; does not mutate `self`.
+    /// Sequence numbers of remaining captures are left unchanged.
+    public func removing(captureID: UUID) -> CaptureSession {
+        CaptureSession(
+            id: id,
+            createdAt: createdAt,
+            state: state,
+            captures: captures.filter { $0.id != captureID },
+            pdfFileName: pdfFileName
+        )
+    }
+
+    /// Value-semantic: returns a new session; does not mutate `self`.
+    public func markArchived(pdfFileName: String) -> CaptureSession {
+        CaptureSession(
+            id: id,
+            createdAt: createdAt,
+            state: .archived,
+            captures: captures,
+            pdfFileName: pdfFileName
+        )
+    }
+}

Sources/ShotdeckCore/Model/ShotdeckError.swift

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+import Foundation
+
+public enum ShotdeckError: Error, LocalizedError, Sendable {
+    case screenRecordingNotGranted
+    case noRegionRemembered
+    case displayNoLongerConnected(displayID: UInt32)
+    case captureFailed(underlying: String)
+    case spoolWriteFailed(path: String, underlying: String)
+    case manifestCorrupt(path: String)
+    case pdfCompositionFailed(reason: String)
+    case airDropUnavailable
+    case noCommentedReturns
+
+    public var errorDescription: String? {
+        switch self {
+        case .screenRecordingNotGranted:
+            return "Screen Recording is turned off. Grant it in System Settings to capture."
+        case .noRegionRemembered:
+            return "No capture region is set. Press ⌥⇧1 to pick one."
+        case .displayNoLongerConnected:
+            return "The display used for capture is no longer connected."
+        case .captureFailed(let underlying):
+            return "The screenshot could not be taken. \(underlying)"
+        case .spoolWriteFailed(_, let underlying):
+            return "The screenshot could not be saved. \(underlying)"
+        case .manifestCorrupt:
+            return "This session's file is damaged and cannot be opened."
+        case .pdfCompositionFailed(let reason):
+            return "The PDF could not be built. \(reason)"
+        case .airDropUnavailable:
+            return "AirDrop is not available right now."
+        case .noCommentedReturns:
+            return "None of the returned PDFs have comments on them."
+        }
+    }
+}