build: SoX Windows 바이너리 직접 번들 (SourceForge 다운로드 차단 우회)

- apps/desktop/resources/sox/sox.exe + 의존 DLL 직접 커밋
- .gitignore 화이트리스트 조정
- download-sox.ps1는 파일 존재 시 자동 스킵하므로 CI에서 그대로 통과

apps/desktop/resources/sox/batch-example.bat

@@ -0,0 +1,14 @@
+rem Example of how to do batch processing with SoX on MS-Windows.
+rem
+rem Place this file in the same folder as sox.exe (& rename it as appropriate).
+rem You can then drag and drop a selection of files onto the batch file (or
+rem onto a `short-cut' to it).
+rem
+rem In this example, the converted files end up in a folder called `converted',
+rem but this, of course, can be changed, as can the parameters to the sox
+rem command.
+
+cd %~dp0
+mkdir converted
+FOR %%A IN (%*) DO sox %%A "converted/%%~nxA" rate -v 44100
+pause