fix(server): 修复 serve-static 不接受数组 root、改为按请求逐个挂载，避免启动时 TypeError: root path must be a string

上一轮把 getBeepAudioDirs() 这个数组直接塞进 express.static()，
但 serve-static 签名要求 root 必须是字符串，会在 app 启动注册
中间件时直接抛错（甚至在接收请求前）。

修复方式：
- /media/audio/general 和 /media/audio/beep 改为动态中间件：
  请求进来时再依次对每个目录调用一次 express.static(root, {fallthrough})
- 单目录的 music/voice/line/station/temp 保留 express.static
  但统一包一层 String(xxx || '') 保证就算路径解析异常也是空
  字符串而不是 undefined
- 后备的 7 条 app.get(':path(*)') 路由不变，仍然负责 sendBinaryFile /
  sendBinaryFileFromCandidates 兜底（含 range、Content-Length 等头）

客户端 bump v1.0.102 -> v1.0.103

CloudServer/server.js

@@ -148,13 +148,35 @@ function safeRelativeToBase(baseDir, relativePath) {
     return full;
 }
 
-app.use('/media/audio/general', express.static(getBeepAudioDirs(), { fallthrough: true }));
-app.use('/media/audio/beep', express.static(getBeepAudioDirs(), { fallthrough: true }));
-app.use('/media/audio/music', express.static(audioMusicDir, { fallthrough: true }));
-app.use('/media/audio/voice', express.static(audioVoiceDir, { fallthrough: true }));
-app.use('/media/audio/line', express.static(audioLineDir, { fallthrough: true }));
-app.use('/media/audio/station', express.static(audioStationDir, { fallthrough: true }));
-app.use('/media/temp', express.static(tempBroadcastDir, { fallthrough: true }));
+app.use('/media/audio/general', (req, res, next) => {
+    const dirs = getBeepAudioDirs();
+    if (!dirs || dirs.length === 0) return next();
+    let i = 0;
+    const tryNext = () => {
+        if (i >= dirs.length) return next();
+        const dir = String(dirs[i++] || '');
+        if (!dir) return tryNext();
+        express.static(dir, { fallthrough: true })(req, res, tryNext);
+    };
+    tryNext();
+});
+app.use('/media/audio/beep', (req, res, next) => {
+    const dirs = getBeepAudioDirs();
+    if (!dirs || dirs.length === 0) return next();
+    let i = 0;
+    const tryNext = () => {
+        if (i >= dirs.length) return next();
+        const dir = String(dirs[i++] || '');
+        if (!dir) return tryNext();
+        express.static(dir, { fallthrough: true })(req, res, tryNext);
+    };
+    tryNext();
+});
+app.use('/media/audio/music', express.static(String(audioMusicDir || ''), { fallthrough: true }));
+app.use('/media/audio/voice', express.static(String(audioVoiceDir || ''), { fallthrough: true }));
+app.use('/media/audio/line', express.static(String(audioLineDir || ''), { fallthrough: true }));
+app.use('/media/audio/station', express.static(String(audioStationDir || ''), { fallthrough: true }));
+app.use('/media/temp', express.static(String(tempBroadcastDir || ''), { fallthrough: true }));
 
 app.get('/media/audio/general/:path(*)', (req, res) => {
     const rel = decodeURIComponent(req.params.path || '');

station_broadcast.lua

@@ -1,6 +1,6 @@
 
 -- 1. Configuration & Constants
-local APP_VERSION_TEXT = "v1.0.102"
+local APP_VERSION_TEXT = "v1.0.103"
 
 local CONFIG = {
     CLOUD_URL = "ws://stabadmin.fse-media.group",