Voice message transcription for the Telegram channel plugin. When a user sends a voice message, the plugin instructs Claude to automatically download the audio file and transcribe it using a user-configured command (OpenAI Whisper, faster-whisper, whisper.cpp, OpenAI API, or any custom script). Claude then receives the spoken text and responds as if the user typed it. Tool-agnostic: any command that reads an audio file and prints text to stdout works. No modifications to the official Telegram plugin required.