feat: Add production migration script for Fly.io deployment

- Create standalone migration script that works in production
- Include migration script and images in Docker build
- Images will be copied to /app/data/images on container start
- Can be run with: node migrate-production.js

backend/Dockerfile

@@ -34,6 +34,10 @@ COPY --from=builder /app/node_modules ./node_modules
 COPY --from=builder /app/dist ./dist
 COPY --from=builder /app/src/db/migrations ./dist/db/migrations
 
+# Copy migration script and migrated images
+COPY --from=builder /app/migrate-production.js ./migrate-production.js
+COPY --from=builder /app/data/images ./data/images
+
 # Create directories
 RUN mkdir -p /app/workspace /app/data