Marknote - Block Editor

This project aims to introduce a robust and high performance block editor and a proper markdown parser to Marknote. Right now, the editor is hard to maintain, full of many condition checks, and has bugs and limitations, especially when handling formatting and advanced features. My plan is to use md4qt to parse Markdown into a structured format and build a block editor that supports things like lists, tables, code blocks, and drag-and-drop. I will design the system so parsing, rendering, editing, and saving are cleanly separated, which will make the app faster, more stable, and easier to extend in the future. I will implement this step by step, making sure all features like undo/redo and export continue to work, and I will test everything properly to ensure a smooth user experience.