Fix ENV trailing comment; disable HF fast downloader safely

Dockerfile

@@ -21,8 +21,10 @@ ENV HF_HOME=/home/appuser/.cache \
     OMP_NUM_THREADS=1 \
     OPENBLAS_NUM_THREADS=1 \
     MKL_NUM_THREADS=1 \
-    PYTHONPATH=/app/backend:$PYTHONPATH \
-    HF_HUB_ENABLE_HF_TRANSFER=0   # disable fast downloader to avoid missing package error
+    PYTHONPATH=/app/backend:$PYTHONPATH
+
+# Disable HF fast downloader (avoids missing hf_transfer during build)
+ENV HF_HUB_ENABLE_HF_TRANSFER=0
 
 # Copy code as appuser
 COPY --chown=appuser:appuser . .
@@ -42,7 +44,7 @@ for pkg in ["punkt","punkt_tab","wordnet","omw-1.4"]:
 print("NLTK OK")
 PY
 
-# Prefetch models (don't fail the build if network hiccups)
+# Prefetch models (non-fatal if network hiccups)
 RUN python - <<'PY'
 from sentence_transformers import SentenceTransformer
 from transformers import AutoTokenizer, AutoModelForTokenClassification