Move gradio pins to requirements.txt, simplify Dockerfile

Dockerfile

@@ -17,8 +17,6 @@ WORKDIR $HOME/app
 # Copy requirements and install (single pip install, pin Gradio 4.44.1)
 COPY --chown=user requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt \
-    "gradio==4.44.1" \
-    "gradio_client<1.0.0" \
     "uvicorn>=0.14.0" \
     "websockets>=10.4"
 

requirements.txt

@@ -7,4 +7,8 @@ diffusers==0.31.0
 transformers==4.44.0
 accelerate==0.33.0
 safetensors==0.4.4
-pillow==10.4.0
+pillow==10.4.0
+
+# Gradio (pinned to avoid 5.0.0 JSON schema bug)
+gradio==4.44.1
+gradio_client<1.0.0