feat(macos): add SurfaceTitleBar — inline-editable split pane title strip

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

@@ -0,0 +1,63 @@
+import SwiftUI
+
+#if canImport(AppKit)
+
+struct SurfaceTitleBar: View {
+    @ObservedObject var surfaceView: Ghostty.SurfaceView
+
+    @State private var isEditing = false
+    @State private var editText = ""
+    @FocusState private var fieldFocused: Bool
+
+    private var displayTitle: String {
+        if surfaceView.isUserSetTitle {
+            return surfaceView.title
+        }
+        return URL(fileURLWithPath: surfaceView.pwd ?? "/").lastPathComponent
+    }
+
+    var body: some View {
+        ZStack {
+            Rectangle()
+                .fill(.ultraThinMaterial)
+
+            if isEditing {
+                TextField("", text: $editText)
+                    .textFieldStyle(.plain)
+                    .multilineTextAlignment(.center)
+                    .focused($fieldFocused)
+                    .onSubmit { commit() }
+                    .onExitCommand { cancel() }
+                    .onChange(of: fieldFocused) { focused in
+                        if !focused { commit() }
+                    }
+                    .padding(.horizontal, 8)
+            } else {
+                Text(displayTitle)
+                    .lineLimit(1)
+                    .truncationMode(.middle)
+                    .foregroundStyle(.secondary)
+                    .onTapGesture(count: 2) { startEditing() }
+            }
+        }
+        .frame(height: 22)
+        .frame(maxWidth: .infinity)
+    }
+
+    private func startEditing() {
+        editText = surfaceView.isUserSetTitle ? surfaceView.title : ""
+        isEditing = true
+        fieldFocused = true
+    }
+
+    private func commit() {
+        surfaceView.setPinnedTitle(editText.isEmpty ? nil : editText)
+        isEditing = false
+    }
+
+    private func cancel() {
+        isEditing = false
+    }
+}
+
+#endif