fix: update Dockerfile for HF Spaces (port 7860, non-root user)

Dockerfile

@@ -1,15 +1,25 @@
 FROM python:3.12-slim
 
 ENV PYTHONDONTWRITEBYTECODE=1 \
-    PYTHONUNBUFFERED=1
+    PYTHONUNBUFFERED=1 \
+    HOME=/home/user \
+    PATH=/home/user/.local/bin:$PATH
 
-WORKDIR /app
+WORKDIR /home/user/app
 
-COPY pyproject.toml README.md ./
-COPY app ./app
+# Create non-root user (required by HuggingFace Spaces)
+RUN useradd -m -u 1000 user
+
+COPY --chown=user pyproject.toml README.md ./
+COPY --chown=user app ./app
 
 RUN pip install --no-cache-dir -e .
 
-EXPOSE 8080
+# Uploads directory writable by non-root user
+RUN mkdir -p /home/user/app/uploads && chown -R user /home/user/app/uploads
+
+USER user
+
+EXPOSE 7860
 
-CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8080"]
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "7860"]