fix: add user 1000 (HF Spaces requirement)

Dockerfile

@@ -1,19 +1,21 @@
 FROM python:3.11-slim
 
+# HuggingFace Spaces requires user ID 1000
 RUN useradd -m -u 1000 user
 
 WORKDIR /home/user/app
 
-# Install dependencies
+# 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 --chown=user *.py .
-
-RUN mkdir -p /home/user/app/checkpoints && chown user:user /home/user/app/checkpoints
+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