refactor(engine): 字幕引擎文件夹重命名，字幕记录添加降序选择

- 字幕记录表格可以按时间降序排列
- 将 caption-engine 重命名为 engine
- 更新了相关文件和文件夹的路径
- 修改了 README 和 TODO 文档中的相关内容
- 更新了 Electron 构建配置

engine/sysaudio/darwin.py

@@ -0,0 +1,85 @@
+"""获取 MacOS 系统音频输入/输出流"""
+
+import pyaudio
+
+
+class AudioStream:
+    """
+    获取系统音频流（支持 BlackHole 作为系统音频输出捕获）
+
+    初始化参数：
+        audio_type: 0-系统音频输出流（需配合 BlackHole），1-系统音频输入流
+        chunk_rate: 每秒采集音频块的数量，默认为20
+    """
+    def __init__(self, audio_type=0, chunk_rate=20):
+        self.audio_type = audio_type
+        self.mic = pyaudio.PyAudio()
+        if self.audio_type == 0:
+            self.device = self.getOutputDeviceInfo()
+        else:
+            self.device = self.mic.get_default_input_device_info()
+        self.stream = None
+        self.SAMP_WIDTH = pyaudio.get_sample_size(pyaudio.paInt16)
+        self.FORMAT = pyaudio.paInt16
+        self.CHANNELS = self.device["maxInputChannels"]
+        self.RATE = int(self.device["defaultSampleRate"])
+        self.CHUNK = self.RATE // chunk_rate
+        self.INDEX = self.device["index"]
+
+    def getOutputDeviceInfo(self):
+        """查找指定关键词的输入设备"""
+        device_count = self.mic.get_device_count()
+        for i in range(device_count):
+            dev_info = self.mic.get_device_info_by_index(i)
+            if 'blackhole' in dev_info["name"].lower():    
+                return dev_info
+        raise Exception("The device containing BlackHole was not found.")
+
+    def printInfo(self):
+        dev_info = f"""
+        采样输入设备：
+            - 设备类型：{ "音频输出" if self.audio_type == 0 else "音频输入" }
+            - 序号：{self.device['index']}
+            - 名称：{self.device['name']}
+            - 最大输入通道数：{self.device['maxInputChannels']}
+            - 默认低输入延迟：{self.device['defaultLowInputLatency']}s
+            - 默认高输入延迟：{self.device['defaultHighInputLatency']}s
+            - 默认采样率：{self.device['defaultSampleRate']}Hz
+
+        音频样本块大小：{self.CHUNK}
+        样本位宽：{self.SAMP_WIDTH}
+        采样格式：{self.FORMAT}
+        音频通道数：{self.CHANNELS}
+        音频采样率：{self.RATE}
+        """
+        print(dev_info)
+
+    def openStream(self):
+        """
+        打开并返回系统音频输出流
+        """
+        if self.stream: return self.stream
+        self.stream = self.mic.open(
+            format = self.FORMAT,
+            channels = int(self.CHANNELS),
+            rate = self.RATE,
+            input = True,
+            input_device_index = int(self.INDEX)
+        )
+        return self.stream
+
+    def read_chunk(self):
+        """
+        读取音频数据
+        """
+        if not self.stream: return None
+        return self.stream.read(self.CHUNK, exception_on_overflow=False)
+
+    def closeStream(self):
+        """
+        关闭系统音频输出流
+        """
+        if self.stream is None: return
+        self.stream.stop_stream()
+        self.stream.close()
+        self.stream = None