An engine with no weights download counted as installed once its venv
interpreter existed, so a dependency install that died halfway made the
next attempt answer already_installed and the engine failed at its first
import. The import probe now writes a completion marker, and a fresh
dependency step removes the old one. IndexTTS keeps its weights check, so
no existing install is asked to reinstall.
The MOSS bootstrap no longer blames a non-CUDA host for an install
failure; the index is always supplied, and uv's error says what failed.
The PocketTTS and Supertonic guides now say where the sidecar runs, and
the three repository-engine guides say what to do if the first weight
download outlasts the compute-time budget.