fix: ffmpeg 路径注入改用 PATH 环境变量方式，确保 pydub 正确找到 ffmpeg

tts_server.py

@@ -10,15 +10,13 @@ from fastapi.responses import FileResponse, StreamingResponse
 from pydantic import BaseModel
 import edge_tts
 
-# pydub 混音支持
+# pydub 混音支持（必须在 import pydub 之前将 ffmpeg 注入 PATH）
+_FFMPEG_BIN = r"C:\Users\maxf\AppData\Local\Microsoft\WinGet\Packages\Gyan.FFmpeg_Microsoft.Winget.Source_8wekyb3d8bbwe\ffmpeg-8.1-full_build\bin"
+if os.path.isdir(_FFMPEG_BIN) and _FFMPEG_BIN not in os.environ.get("PATH", ""):
+    os.environ["PATH"] = _FFMPEG_BIN + os.pathsep + os.environ.get("PATH", "")
+
 try:
     from pydub import AudioSegment
-    # 指定 ffmpeg 路径（WinGet 安装路径）
-    FFMPEG_PATH = r"C:\Users\maxf\AppData\Local\Microsoft\WinGet\Packages\Gyan.FFmpeg_Microsoft.Winget.Source_8wekyb3d8bbwe\ffmpeg-8.1-full_build\bin\ffmpeg.exe"
-    FFPROBE_PATH = r"C:\Users\maxf\AppData\Local\Microsoft\WinGet\Packages\Gyan.FFmpeg_Microsoft.Winget.Source_8wekyb3d8bbwe\ffmpeg-8.1-full_build\bin\ffprobe.exe"
-    if os.path.exists(FFMPEG_PATH):
-        AudioSegment.converter = FFMPEG_PATH
-        AudioSegment.ffprobe = FFPROBE_PATH
     PYDUB_AVAILABLE = True
 except ImportError:
     PYDUB_AVAILABLE = False