fix: restructure Dockerfile to do all setup as root, then switch to user

Dockerfile

@@ -13,24 +13,28 @@ RUN apt-get update && apt-get install -y \
 
 # Create user for Hugging Face Spaces (following HF Spaces best practices)
 RUN useradd -m -u 1000 user
-USER user
-ENV PATH="/home/user/.local/bin:$PATH"
 
 # Set working directory
 WORKDIR /app
 
 # Copy requirements file
-COPY --chown=user:user ./requirements.txt requirements.txt
+COPY requirements.txt requirements.txt
 
-# Install Python dependencies
+# Install Python dependencies as root
 RUN pip install --no-cache-dir --upgrade pip && \
-    pip install --no-cache-dir --user -r requirements.txt
+    pip install --no-cache-dir -r requirements.txt
 
 # Copy application code
-COPY --chown=user:user . /app
+COPY . /app
+
+# Create upload directories and set ownership
+RUN mkdir -p uploads/source_images uploads/target_videos uploads/result_videos uploads/output && \
+    chown -R user:user /app && \
+    chmod -R 755 uploads
 
-# Create upload directories
-RUN mkdir -p uploads/source_images uploads/target_videos uploads/result_videos uploads/output
+# Switch to user
+USER user
+ENV PATH="/home/user/.local/bin:$PATH"
 
 # Set environment variables
 ENV PYTHONUNBUFFERED=1