fix: remove mkdir steps - application creates directories automatically

Dockerfile

@@ -27,10 +27,6 @@ RUN pip install --no-cache-dir --upgrade pip && \
 # Copy application code with ownership
 COPY --chown=user:user . /app
 
-# Create upload directories
-RUN mkdir -p uploads/source_images uploads/target_videos uploads/result_videos uploads/output && \
-    chmod -R 755 uploads
-
 # Switch to user
 USER user
 ENV PATH="/home/user/.local/bin:$PATH"