Explain why dedicated-venv engines (IndexTTS2) add disk (a second torch +
CUDA libs: Linux cu128 ~0.83 GiB, Windows ~3.2 GiB), and how uv's link-mode
dedup (clone on macOS/Linux, hardlink on Windows) shares identical wheels
for free — provided UV_CACHE_DIR and the venvs are on the same filesystem.
Key policy: pin the same torch build as the parent whenever the engine
allows, since only identical wheels dedupe; UV_LINK_MODE=hardlink on Linux
ext4. Linked from the IndexTTS engine doc.
Spec §R4(a) / parity program Wave 4.5.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
