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/linux.py

@@ -0,0 +1,94 @@
+"""获取 Linux 系统音频输入流"""
+
+import subprocess
+
+def findMonitorSource():
+    result = subprocess.run(
+        ["pactl", "list", "short", "sources"],
+        stdout=subprocess.PIPE, text=True
+    )
+    lines = result.stdout.splitlines()
+
+    for line in lines:
+        parts = line.split('\t')
+        if len(parts) >= 2 and ".monitor" in parts[1]:
+            return parts[1]
+
+    raise RuntimeError("System output monitor device not found")
+
+def findInputSource():
+    result = subprocess.run(
+        ["pactl", "list", "short", "sources"],
+        stdout=subprocess.PIPE, text=True
+    )
+    lines = result.stdout.splitlines()
+
+    for line in lines:
+        parts = line.split('\t')
+        name = parts[1]
+        if ".monitor" not in name:
+            return name
+    raise RuntimeError("Microphone input device not found")
+
+class AudioStream:
+    """
+    获取系统音频流
+
+    初始化参数：
+        audio_type: 0-系统音频输出流（不支持，不会生效），1-系统音频输入流（默认）
+        chunk_rate: 每秒采集音频块的数量，默认为20
+    """
+    def __init__(self, audio_type=1,  chunk_rate=20):
+        self.audio_type = audio_type
+
+        if self.audio_type == 0:
+            self.source = findMonitorSource()
+        else:
+            self.source = findInputSource()
+
+        self.process = None
+
+        self.SAMP_WIDTH = 2
+        self.FORMAT = 16
+        self.CHANNELS = 2
+        self.RATE = 48000
+        self.CHUNK = self.RATE // chunk_rate
+
+    def printInfo(self):
+        dev_info = f"""
+        音频捕获进程：
+            - 捕获类型：{"音频输出" if self.audio_type == 0 else "音频输入"}
+            - 设备源：{self.source}
+            - 捕获进程PID：{self.process.pid if self.process else "None"}
+
+        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):
+        """
+        启动音频捕获进程
+        """
+        self.process = subprocess.Popen(
+            ["parec", "-d", self.source, "--format=s16le", "--rate=48000", "--channels=2"],
+            stdout=subprocess.PIPE
+        )
+
+    def read_chunk(self):
+        """
+        读取音频数据
+        """
+        if self.process:
+            return self.process.stdout.read(self.CHUNK)
+        return None
+
+    def closeStream(self):
+        """
+        关闭系统音频捕获进程
+        """
+        if self.process:
+            self.process.terminate()