macos: start work on SlideTerminal, slides in window from top

macos/Sources/Features/SlideTerminal/SlideTerminalController.swift

@@ -0,0 +1,62 @@
+import Foundation
+import Cocoa
+import SwiftUI
+import GhosttyKit
+
+/// Controller for the slide-style terminal.
+class SlideTerminalController: NSWindowController {
+    override var windowNibName: NSNib.Name? { "SlideTerminal" }
+
+    override func windowDidLoad() {
+        guard let window = self.window else { return }
+
+        // Make the window full width
+        let screenFrame = NSScreen.main?.frame ?? .zero
+        window.setFrame(NSRect(
+            x: 0,
+            y: 0,
+            width: screenFrame.size.width,
+            height: window.frame.size.height
+        ), display: false)
+
+        slideWindowIn(window: window)
+    }
+
+    private func slideWindowIn(window: NSWindow) {
+        guard let screen = NSScreen.main else { return }
+
+        // Determine our final position. Our final position is exactly
+        // pinned against the top menu bar.
+        let windowFrame = window.frame
+        let finalY = screen.visibleFrame.maxY - windowFrame.height
+
+        // Move our window off screen to the top
+        window.setFrameOrigin(.init(
+            x: windowFrame.origin.x,
+            y: screen.frame.maxY))
+
+        // Set the window invisible
+        window.alphaValue = 0
+
+        // Move it to the visible position since animation requires this
+        window.makeKeyAndOrderFront(nil)
+
+        // Run the animation that moves our window into the proper place and makes
+        // it visible.
+        NSAnimationContext.runAnimationGroup { context in
+            context.duration = 0.3
+            context.timingFunction = .init(name: .easeIn)
+
+            let animator = window.animator()
+            animator.setFrame(.init(
+                origin: .init(x: windowFrame.origin.x, y: finalY),
+                size: windowFrame.size
+            ), display: true)
+            animator.alphaValue = 1
+        }
+    }
+}
+
+enum SlideTerminalLocation {
+    case top
+}