Develop a Design Feedback Tool web application using React, Node.js, Express, Tailwind CSS, and MongoDB. Implement drag-and-drop high-resolution image uploads for UI/UX mockups stored securely via Cloudinary. Build an interactive Review Workspace where clients and team members can click directly on uploaded mockup images to drop numbered pin comments with contextual text feedback. Calculate relative X and Y coordinate percentages so pin markers remain accurately positioned regardless of screen size or device scaling. Build a slide-out comment drawer displaying threaded conversations, assignee tags, and resolve/unresolve toggles. Generate public shareable guest review links requiring no client login, with optional password protection. Implement real-time email alerts via SendGrid when clients add new pin comments. Include version history comparison views, Figma plugin sync support, and resolved pin filter controls.