Shotomatic

Build me a local macOS screenshot automation app covering Shotomatic's basic loop. Requirements: - Use SwiftUI and ScreenCaptureKit in a native macOS 14+ app with no third-party packages. - Provide a source picker for one display or one visible window, with thumbnail previews. - Let me set an interval in seconds and stop after a screenshot count or elapsed duration. - Show a three-second countdown, live running status, captured count, and a clear Stop button. - Save every capture as PNG or JPEG in ~/Pictures/Capture Sessions/<timestamp>/. - Keep a local session list with thumbnails; open a session in Finder or delete it with confirmation. - Add one optional keypress after each capture using CGEvent so paged content can advance. - Check Screen Recording and Accessibility permission before starting; explain how to grant each. - Never upload files, add accounts, or collect telemetry. The app must work fully offline. - Handle a display or window disappearing mid-session without losing images already captured. - Include a small unit-tested state machine for idle, countdown, running, stopping, and failed states. - Include a README with build, permission, and signing notes plus a manual smoke-test checklist. - Out of scope: custom-area capture, website batches, guide editing, annotations, PDF/ZIP/MP4 export. - Produce an Xcode project that builds and runs, then run the unit tests before finishing.