fix: add user 1000 (HF Spaces requirement)

Dockerfile

@@ -1,14 +1,23 @@
 FROM python:3.11-slim
 
-WORKDIR /app
+# HuggingFace Spaces requires user ID 1000
+RUN useradd -m -u 1000 user
 
-# Install dependencies
-COPY requirements.txt .
+WORKDIR /home/user/app
+
+# Install dependencies (CPU-only torch to keep image small)
+COPY --chown=user requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt \
     --extra-index-url https://download.pytorch.org/whl/cpu
 
 # Copy application code
-COPY . .
+COPY --chown=user symbio_model.py .
+COPY --chown=user tokenizer.py .
+COPY --chown=user server.py .
+
+# Switch to non-root user
+USER user
+ENV HOME=/home/user
 
 EXPOSE 7860