stacks/index-tts: install git-lfs in image so examples come down real

The IndexTTS-2 repo stores examples/emo_*.wav and examples/voice_*.wav
as Git LFS objects. v1 of our image cloned the repo without an LFS
pull, leaving those paths as ~130-byte pointer text files — unusable
for `docker cp` into /worktank/index-tts/{voices,emotions}/ as starter
references. (Caught when an emotion_voice="hate" call returned audio
that was actually the pointer text round-tripped through file IO.)

v2 adds git-lfs to the apt list, calls `git lfs install --system`
once, and `git lfs pull` after the checkout. Adds ~1-2 MB to the
image (the examples are small audio clips). INDEX_TTS_TAG bumped to
v2 to force a clean rebuild.

stacks/index-tts/.env.example

@@ -6,8 +6,10 @@
 INDEX_TTS_SHA=830f6f8f94a51fea23ab1d639027a86200075a4e
 
 # Local image tag — bump when you change build context (Dockerfile,
-# app.py, entrypoint.sh) to force a fresh layer build.
-INDEX_TTS_TAG=v1
+# app.py, entrypoint.sh) to force a fresh layer build. v2 = git-lfs
+# added so the example WAVs in /opt/index-tts/examples/ come down as
+# real audio (v1 left them as LFS pointer stubs).
+INDEX_TTS_TAG=v2
 
 # ── network ──────────────────────────────────────────────────────────
 # Host port. Container listens on 8000 internally.

stacks/index-tts/Dockerfile

@@ -15,16 +15,25 @@ ENV DEBIAN_FRONTEND=noninteractive \
 RUN apt-get update \
  && apt-get install -y --no-install-recommends \
         python3.10 python3.10-venv python3-pip \
-        git ffmpeg libsndfile1 \
+        git git-lfs ffmpeg libsndfile1 \
         ca-certificates wget \
  && rm -rf /var/lib/apt/lists/* \
- && python3.10 -m venv /opt/venv
+ && python3.10 -m venv /opt/venv \
+ && git lfs install --system
 
 # Pinned IndexTTS-2 SHA — bump in stack .env (INDEX_TTS_SHA build arg)
 # when you want upstream updates.
+#
+# `git lfs pull` after the checkout fetches examples/emo_*.wav and the
+# example/voice_*.wav reference clips that are stored as LFS objects.
+# Without it, the .wav files come down as ~130-byte LFS pointer text
+# files, and `docker cp`-ing them out as starter material for
+# /worktank/index-tts/{voices,emotions} produces unusable garbage.
 ARG INDEX_TTS_SHA=830f6f8f94a51fea23ab1d639027a86200075a4e
 RUN git clone https://github.com/index-tts/index-tts.git /opt/index-tts \
- && cd /opt/index-tts && git checkout ${INDEX_TTS_SHA}
+ && cd /opt/index-tts \
+ && git checkout ${INDEX_TTS_SHA} \
+ && git lfs pull
 
 # CUDA 12.8 torch wheels (per IndexTTS pyproject.toml's tool.uv.index
 # pin — same versions, same source).