Add optional audio dependencies and FFmpeg note to requirements.txt

requirements.txt

@@ -1,9 +1,23 @@
 gradio[full]
 gradio[mcp]
-llama-index==0.6.9
-openai==0.27.0
+
+# core Llama-Index + HF model support
+llama-index
+openai
 transformers
 torch
 accelerate
+
+# optional extras
 langchain
-langchain-community
+langchain-community
+
+# audio input (choose at least one):
+sounddevice       # cross-platform realtime mic capture
+pyaudio           # alternative on Windows
+
+# (system requirement, not a pip package)
+#   • ffmpeg must be installed on your machine for any audio I/O
+#     • Debian/Ubuntu: sudo apt install ffmpeg
+#     • macOS (homebrew): brew install ffmpeg
+#     • Windows: download from https://ffmpeg.org/download.html