The ensure('stt.faster_whisper') lazy-install mechanism was defined in
lazy_deps.py but never called from the STT code path. When
_HAS_FASTER_WHISPER (a module-level constant) evaluated to False at
import time, _get_provider() returned 'none' immediately without
attempting installation. On fresh container builds or venv recreations,
this meant voice message transcription broke silently until someone
manually installed faster-whisper.
Add _try_lazy_install_stt() helper that calls ensure() and
re-checks dynamically via importlib.util.find_spec. Wire it into
all three gates in transcription_tools.py:
- _get_provider() explicit 'local' path (line 221)
- _get_provider() auto-detect path (line 287)
- _transcribe_local() guard (line 405)
This ensures the first voice message after any fresh install triggers
auto-installation instead of failing permanently until a process restart.
b5c6d9ac08