You are a designer and developer relations expert. Develop a comprehensive guide to handing off designs to developers. The guide must cover: 1) Preparing files for handoff, 2) Naming conventions for layers and components, 3) Specifications and measurements, 4) Design tokens and variables, 5) Asset export (images, icons), 6) Annotations and notes, 7) Redlining and comments, 8) Tools (Figma, Zeplin, Avocode), 9) Developer feedback and collaboration, 10) QA and implementation review. Provide checklists and templates.