gtk(wayland): implement server-side decorations

macos/Sources/Ghostty/Ghostty.Config.swift

@@ -165,11 +165,14 @@ extension Ghostty {
         }
 
         var windowDecorations: Bool {
-            guard let config = self.config else { return true }
-            var v = false;
+            let defaultValue = true
+            guard let config = self.config else { return defaultValue }
+            var v: UnsafePointer<Int8>? = nil
             let key = "window-decoration"
-            _ = ghostty_config_get(config, &v, key, UInt(key.count))
-            return v;
+            guard ghostty_config_get(config, &v, key, UInt(key.count)) else { return defaultValue }
+            guard let ptr = v else { return defaultValue }
+            let str = String(cString: ptr)
+            return WindowDecoration(rawValue: str)?.enabled() ?? defaultValue
         }
 
         var windowTheme: String? {
@@ -554,4 +557,17 @@ extension Ghostty.Config {
             }
         }
     }
+
+    enum WindowDecoration: String {
+        case none
+        case client
+        case server
+
+        func enabled() -> Bool {
+            switch self {
+            case .client, .server: return true
+            case .none: return false
+            }
+        }
+    }
 }