macos: surface focus follow mouse

macos/Sources/Features/Terminal/TerminalController.swift

@@ -197,9 +197,10 @@ class TerminalController: NSWindowController, NSWindowDelegate,
             window.isOpaque = true
             window.backgroundColor = .windowBackgroundColor
         }
-        
+
         window.hasShadow = ghostty.config.macosWindowShadow
-        
+        window.focusFollowsMouse = ghostty.config.focusFollowsMouse
+
         guard window.hasStyledTabs else { return }
 
         // The titlebar is always updated. We don't need to worry about opacity

macos/Sources/Features/Terminal/TerminalWindow.swift

@@ -369,6 +369,8 @@ class TerminalWindow: NSWindow {
         }
     }
 
+    var focusFollowsMouse: Bool = false
+
     // Find the NSTextField responsible for displaying the titlebar's title.
     private var titlebarTextField: NSTextField? {
         guard let titlebarContainer = contentView?.superview?.subviews

macos/Sources/Ghostty/SurfaceView_AppKit.swift

@@ -480,6 +480,10 @@ extension Ghostty {
             let pos = self.convert(event.locationInWindow, from: nil)
             ghostty_surface_mouse_pos(surface, pos.x, frame.height - pos.y)
 
+            guard let window = self.window as? TerminalWindow else { return }
+            if !self.focused && window.focusFollowsMouse {
+                Ghostty.moveFocus(to: self)
+            }
         }
 
         override func mouseDragged(with event: NSEvent) {