macos: restrict resizing based on sliding terminal position

macos/Sources/Features/SlideTerminal/SlideTerminalController.swift

@@ -10,7 +10,7 @@ class SlideTerminalController: NSWindowController, NSWindowDelegate, TerminalVie
     /// The app instance that this terminal view will represent.
     let ghostty: Ghostty.App
 
-    /// The position fo the slide terminal.
+    /// The position for the slide terminal.
     let position: SlideTerminalPosition
 
     /// The surface tree for this window.
@@ -65,6 +65,11 @@ class SlideTerminalController: NSWindowController, NSWindowDelegate, TerminalVie
         slideOut()
     }
 
+    func windowWillResize(_ sender: NSWindow, to frameSize: NSSize) -> NSSize {
+        guard let screen = NSScreen.main else { return frameSize }
+        return position.restrictFrameSize(frameSize, on: screen)
+    }
+
     //MARK: TerminalViewDelegate
 
     func cellSizeDidChange(to: NSSize) {

macos/Sources/Features/SlideTerminal/SlideTerminalPosition.swift

@@ -35,6 +35,17 @@ enum SlideTerminalPosition {
         }
     }
 
+    /// Restrict the frame size during resizing.
+    func restrictFrameSize(_ size: NSSize, on screen: NSScreen) -> NSSize {
+        var finalSize = size
+        switch (self) {
+        case .top:
+            finalSize.width = screen.frame.width
+        }
+
+        return finalSize
+    }
+
     /// The initial point origin for this position.
     func initialOrigin(for window: NSWindow, on screen: NSScreen) -> CGPoint {
         switch (self) {