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

macos/Sources/Features/SlideTerminal/SlideTerminal.xib

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="23094" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+    <dependencies>
+        <deployment identifier="macosx"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="23094"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <objects>
+        <customObject id="-2" userLabel="File's Owner" customClass="SlideTerminalController" customModule="Ghostty" customModuleProvider="target">
+            <connections>
+                <outlet property="window" destination="QvC-M9-y7g" id="JMU-zX-9Ie"/>
+            </connections>
+        </customObject>
+        <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
+        <customObject id="-3" userLabel="Application" customClass="NSObject"/>
+        <window title="👻 Ghostty" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" restorable="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" id="QvC-M9-y7g" customClass="SlideTerminalWindow" customModule="Ghostty" customModuleProvider="target">
+            <windowStyleMask key="styleMask" titled="YES" closable="YES" miniaturizable="YES" resizable="YES"/>
+            <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
+            <rect key="contentRect" x="196" y="240" width="480" height="270"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="3008" height="1667"/>
+            <view key="contentView" wantsLayer="YES" id="EiT-Mj-1SZ">
+                <rect key="frame" x="0.0" y="0.0" width="480" height="270"/>
+                <autoresizingMask key="autoresizingMask"/>
+            </view>
+            <connections>
+                <outlet property="delegate" destination="-2" id="u5f-FR-jJw"/>
+            </connections>
+            <point key="canvasLocation" x="132" y="-82"/>
+        </window>
+    </objects>
+</document>

macos/Sources/Features/SlideTerminal/SlideTerminalController.swift

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+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
+}

macos/Sources/Features/SlideTerminal/SlideTerminalWindow.swift

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+import Cocoa
+
+class SlideTerminalWindow: NSWindow {
+    // Both of these must be true for windows without decorations to be able to
+    // still become key/main and receive events.
+    override var canBecomeKey: Bool { return true }
+    override var canBecomeMain: Bool { return true }
+    
+    override func awakeFromNib() {
+        super.awakeFromNib()
+
+        // Note: almost all of this stuff can be done in the nib/xib directly
+        // but I prefer to do it programmatically because the properties we
+        // care about are less hidden.
+
+        // Remove the title completely. This will make the window square. One
+        // downside is it also hides the cursor indications of resize but the
+        // window remains resizable.
+        self.styleMask.remove(.titled)
+
+        // We need to set our window level to a high value. In testing, only
+        // popUpMenu and above do what we want. This gets it above the menu bar
+        // and lets us render off screen.
+        self.level = .popUpMenu
+
+        self.isMovableByWindowBackground = true
+        self.isMovable = true
+
+        self.collectionBehavior = [
+            // We want this to be part of every space because it is a singleton.
+            .canJoinAllSpaces,
+
+            // We don't want to be part of command-tilde
+            .ignoresCycle,
+
+            // We never support fullscreen
+            .fullScreenNone]
+    }
+}