macOS: move `hoverUrl` to `OSSurfaceView`

macos/Sources/Ghostty/Surface View/OSSurfaceView.swift

@@ -25,6 +25,9 @@ extension Ghostty {
         // Any error while initializing the surface.
         @Published var error: Error?
 
+        // The hovered URL string
+        @Published var hoverUrl: String?
+
         init(id: UUID?, frame: CGRect) {
             self.id = id ?? UUID()
             super.init(frame: frame)

macos/Sources/Ghostty/Surface View/SurfaceView_AppKit.swift

@@ -21,9 +21,6 @@ extension Ghostty {
             }
         }
 
-        // The hovered URL string
-        @Published var hoverUrl: String?
-
         // The progress report (if any)
         @Published var progressReport: Action.ProgressReport? {
             didSet {

macos/Sources/Ghostty/Surface View/SurfaceView_UIKit.swift

@@ -9,9 +9,6 @@ extension Ghostty {
         // to the app level and it is set from there.
         @Published var title: String = "👻"
 
-        // The hovered URL
-        @Published var hoverUrl: String?
-
         // The progress report (if any)
         @Published var progressReport: Action.ProgressReport?