* feat: add Telegram voice/audio transcription via whisper.cpp
Telegram voice notes and audio attachments are now transcribed locally
using whisper.cpp before being sent to the agent. Includes auto-download
of Whisper models, ffmpeg fallback for non-WAV formats, configurable
settings under telegram.audioInput, and unit tests for the new STT layer.
* fix: harden whisper audio setup
Avoid Linux model download failures, remove unused STT dependencies, and keep local Cursor state changes isolated to the intended files.
* refactor: share Telegram audio handler
Reduce duplicate Telegram voice and audio handling so transcription flow changes stay in sync.