Refactor Dockerfile for improved user setup and dependency installation

Dockerfile

@@ -1,38 +1,30 @@
 FROM python:3.9-slim
 
-# Install system dependencies for OpenCV
+# 1. Install system dependencies for OpenCV
 RUN apt-get update && apt-get install -y \
     libgl1 \
     libglib2.0-0 \
     && rm -rf /var/lib/apt/lists/*
 
-# Set up a new user named "user" with user ID 1000
+# 2. Set up a non-root user for Hugging Face Spaces
 RUN useradd -m -u 1000 user
+WORKDIR /app
+RUN chown user:user /app
 
-# Switch to user
 USER user
 ENV PATH="/home/user/.local/bin:$PATH"
 
-# Set working directory (this will be owned by root if we don't be careful, but user can write to their home)
-# Better practice: create the dir as root, chown it, then switch user. 
-# But standard pattern: just work in home or ensure pre-creation.
-# Let's simplify: Work in /app but ensure we have permissions.
-USER root
-RUN mkdir /app && chown user:user /app
-USER user
-
-WORKDIR /app
-
-# Copy requirements and install
-COPY --chown=user requirements.txt requirements.txt
+# 3. Install Python dependencies
+COPY --chown=user requirements.txt .
 RUN pip install --no-cache-dir --upgrade pip && \
     pip install --no-cache-dir --user -r requirements.txt
 
-# Copy application code
-COPY --chown=user app.py app.py
+# 4. PRE-DOWNLOAD THE MODEL (This prevents the "stuck" build/startup)
+RUN python -c "from ultralytics import YOLO; YOLO('yolov8n-pose.pt')"
+
+# 5. Copy the app code
+COPY --chown=user app.py .
 
-# Expose the Hugging Face Spaces port
 EXPOSE 7860
 
-# Run the application
-CMD ["python", "app.py"]
+CMD ["python", "app.py"]