Add audio format selection for audio-only downloads

Introduces settings and UI for forcing audio format conversion on audio-only downloads, including support for selecting preferred audio formats. Updates language files for all supported languages, adds config options, and passes new settings through the downloader and main app logic.

languages/id.json

@@ -293,7 +293,19 @@
     "force_format_help": "Jika diaktifkan, video yang digabungkan akan dikonversi ke format pilihan Anda. Nonaktifkan untuk membiarkan yt-dlp memutuskan secara otomatis.",
     "format_mp4": "MP4 (Paling kompatibel)",
     "format_webm": "WebM (Modern, terbuka)",
-    "format_mkv": "MKV (Kaya fitur)"
+    "format_mkv": "MKV (Kaya fitur)",
+    "audio_format_settings": "Pengaturan Format Audio",
+    "force_audio_format": "Paksa format audio untuk unduhan khusus audio",
+    "preferred_audio_format": "Format audio pilihan:",
+    "force_audio_format_help": "Saat diaktifkan, unduhan khusus audio akan dikonversi ke format pilihan Anda. Ini hanya berlaku saat mengunduh format audio.",
+    "audio_format_best": "Terbaik (Tanpa konversi)",
+    "audio_format_aac": "AAC (Bagus untuk editing)",
+    "audio_format_mp3": "MP3 (Universal)",
+    "audio_format_flac": "FLAC (Lossless)",
+    "audio_format_wav": "WAV (Tidak terkompresi)",
+    "audio_format_opus": "Opus (Efisien)",
+    "audio_format_m4a": "M4A (Apple)",
+    "audio_format_vorbis": "Vorbis (Terbuka)"
   },
   "main_ui": {
     "url_placeholder": "Masukkan URL video atau playlist YouTube",