feat: 模态提示框

PCL.Mac/App/AppRouter.swift

@@ -119,6 +119,5 @@ class AppRouter: ObservableObject {
         }
     }
 
-    private init() {
-    }
+    private init() {}
 }

PCL.Mac/App/MessageBoxManager.swift

@@ -0,0 +1,23 @@
+//
+//  MessageBoxManager.swift
+//  PCL.Mac
+//
+//  Created by 温迪 on 2026/1/20.
+//
+
+import Foundation
+
+class MessageBoxManager: ObservableObject {
+    public static let shared: MessageBoxManager = .init()
+    @Published public private(set) var currentMessageBox: MessageBox?
+
+    public func showText(title: String, body: String, level: MessageBox.Level = .info) {
+        currentMessageBox = .init(title: title, body: .text(text: body), level: level)
+    }
+
+    public func close() {
+        currentMessageBox = nil
+    }
+
+    private init() {}
+}

PCL.Mac/Models/MessageBox.swift

@@ -0,0 +1,22 @@
+//
+//  MessageBox.swift
+//  PCL.Mac
+//
+//  Created by 温迪 on 2026/1/20.
+//
+
+import Foundation
+
+struct MessageBox {
+    public let title: String
+    public let body: Body
+    public let level: Level
+
+    public enum Body {
+        case text(text: String)
+    }
+
+    public enum Level {
+        case info, error
+    }
+}