v4: pin huggingface_hub<1.0 (Gradio 4.x needs HfFolder, removed in hub 1.0)

requirements.txt

@@ -3,12 +3,12 @@ matplotlib>=3.7
 numpy>=1.24
 torch>=2.0
 pillow>=10.0
-huggingface_hub>=0.24
+# huggingface_hub <1.0 — Gradio 4.x imports HfFolder which was removed in 1.0.
+huggingface_hub>=0.24,<1.0
 
 # llama-cpp-python: prebuilt wheel from AIencoder/llama-cpp-wheels.
-# CPU-only (no BLAS dep), AVX2 + FMA + F16C — the right baseline for HF
-# Spaces' x86_64 CPU. Avoids source-build, which is unreliable on Spaces.
+# CPU-only, AVX2 + FMA + F16C — the right baseline for HF Spaces' x86_64.
+# Avoids source-build, which is unreliable on Spaces.
 https://huggingface.co/datasets/AIencoder/llama-cpp-wheels/resolve/main/llama_cpp_python-0.3.16%2Bbasic_avx2_fma_f16c-cp312-cp312-manylinux_2_31_x86_64.whl
 
-# Backport for stdlib audioop, removed in Python 3.13.
 audioop-lts; python_version >= "3.13"