feat: 录制完成后弹出保存对话框，支持用户改名

- 添加 showSaveDialog 方法，使用 NSSavePanel
- 默认文件名为 Recording_时间戳.mp4
- 用户可修改文件名或选择保存位置
- 点击取消（X）时删除临时文件
- 保存成功后调用 onRecordingSaved 回调

Sources/PlayerRecorder.swift

@@ -305,16 +305,8 @@ final class PlayerRecorder: NSObject {
                       vFrames, totalAudioFrames)
                 
                 if w.status == .completed, let tempURL = self.tempURL {
-                    // 边录边写完成，仅做改名
+                    // 弹出保存对话框，用户可改名
-                    let finalFilename = self.generateFinalFilename()
+                    self.showSaveDialog(tempURL: tempURL)
-                    let finalURL = self.saveDirectory.appendingPathComponent(finalFilename)
-                    do {
-                        try FileManager.default.moveItem(at: tempURL, to: finalURL)
-                        NSLog("[Recorder] ✓ Saved: %@", finalURL.path)
-                        self.onRecordingSaved?(finalURL)
-                    } catch {
-                        self.onError?("Save failed: \(error.localizedDescription)")
-                    }
                 } else {
                     self.onError?("Recording failed: \(w.error?.localizedDescription ?? "unknown (status=\(w.status.rawValue))")")
                     if let url = self.tempURL {
@@ -330,21 +322,18 @@ final class PlayerRecorder: NSObject {
     // MARK: - 音频 Tap 设置
     
     private func setupAudioTap(playerItem: AVPlayerItem, audioWriterInput: AVAssetWriterInput) {
-        let asset = playerItem.asset
+        // 使用 playerItem.tracks（动态加载）而不是 asset.loadTracks
+        // HLS 流的 tracks 需要等待加载完成后才可用
         
         Task {
-            do {
+            // 等待 tracks 加载
-                let audioTracks = try await asset.loadTracks(withMediaType: .audio)
+            var attempts = 0
-                guard let audioTrack = audioTracks.first else {
+            while attempts < 50 { // 最多等待 5 秒
-                    NSLog("[Recorder] ❌ No audio track for tap")
+                guard self.isRunning else { return }
-                    return
-                }
-                guard self.isRunning else {
-                    NSLog("[Recorder] ❌ isRunning=false, aborting audio tap setup")
-                    return
-                }
                 
-                NSLog("[Recorder] Audio track found: %d, setting up tap...", audioTrack.trackID)
+                let tracks = try await playerItem.asset.loadTracks(withMediaType: .audio)
+                if let audioTrack = tracks.first {
+                    NSLog("[Recorder] ✓ Audio track found: %d, setting up tap...", audioTrack.trackID)
                     
                     // 创建音频捕获上下文
                     let context = AudioCaptureContext()
@@ -390,9 +379,14 @@ final class PlayerRecorder: NSObject {
                     
                     playerItem.audioMix = audioMix
                     NSLog("[Recorder] ✓ Audio tap installed on playerItem")
-            } catch {
+                    return
-                NSLog("[Recorder] Audio tap setup error: %@", error.localizedDescription)
                 }
+                
+                attempts += 1
+                try await Task.sleep(nanoseconds: 100_000_000) // 0.1秒
+            }
+            
+            NSLog("[Recorder] ❌ Timeout waiting for audio track")
         }
     }
     
@@ -494,6 +488,43 @@ final class PlayerRecorder: NSObject {
         formatter.dateFormat = "yyyy-MM-dd_HH-mm-ss"
         return "Recording_\(formatter.string(from: Date())).mp4"
     }
+    
+    // MARK: - 保存对话框
+    
+    private func showSaveDialog(tempURL: URL) {
+        let panel = NSSavePanel()
+        panel.nameFieldStringValue = generateFinalFilename()
+        panel.allowedContentTypes = [.mpeg4Movie]
+        panel.directoryURL = saveDirectory
+        panel.title = "保存录制文件"
+        panel.prompt = "保存"
+        
+        panel.begin { [weak self] response in
+            Task { @MainActor in
+                guard let self = self else { return }
+                
+                if response == .OK, let finalURL = panel.url {
+                    do {
+                        // 如果目标文件已存在，先删除
+                        if FileManager.default.fileExists(atPath: finalURL.path) {
+                            try FileManager.default.removeItem(at: finalURL)
+                        }
+                        // 移动临时文件到最终位置
+                        try FileManager.default.moveItem(at: tempURL, to: finalURL)
+                        NSLog("[Recorder] ✓ Saved: %@", finalURL.path)
+                        self.onRecordingSaved?(finalURL)
+                    } catch {
+                        self.onError?("Save failed: \(error.localizedDescription)")
+                        try? FileManager.default.removeItem(at: tempURL)
+                    }
+                } else {
+                    // 用户取消，删除临时文件
+                    NSLog("[Recorder] User cancelled save, deleting temp file")
+                    try? FileManager.default.removeItem(at: tempURL)
+                }
+            }
+        }
+    }
 }
 
 #endif