fix: resolve huggingface space deployment permission and missing uploads dir issue

Dockerfile

@@ -1,14 +1,24 @@
 FROM node:20-bullseye-slim
 
+# Create app directory and set ownership to the existing 'node' user (UID 1000)
+RUN mkdir -p /app && chown node:node /app
 WORKDIR /app
 
-COPY frontend/package.json ./frontend/package.json
-COPY backend/package.json backend/package-lock.json ./backend/
+# Switch to the non-root user
+USER node
+
+# Copy package files with correct ownership
+COPY --chown=node:node frontend/package.json ./frontend/package.json
+COPY --chown=node:node backend/package.json backend/package-lock.json ./backend/
 
 RUN npm --prefix frontend install --no-audit --no-fund && npm --prefix backend ci
 
-COPY frontend ./frontend
-COPY backend ./backend
+# Copy source code with correct ownership
+COPY --chown=node:node frontend ./frontend
+COPY --chown=node:node backend ./backend
+
+# Create uploads directory so backend can serve static files
+RUN mkdir -p backend/uploads
 
 RUN npm --prefix frontend run build && npm --prefix backend run build