…wn blocks

- Removed the Block stories for React and Vue as they are now integrated into the Drag stories.
- Added new Drag stories for PlainText, Markdown, and ReadOnly modes, showcasing drag-and-drop capabilities.
- Introduced block-level markdown options to support drag mode, ensuring proper handling of adjacent text and marks.
- Created comprehensive tests for drag functionality, including row addition, deletion, and menu interactions.
- Enhanced the MarkedInput component to support drag behavior, allowing for intuitive reordering of content.

- Updated `addDragRow` to ensure two empty rows are created when the value is empty and a double separator is used.
- Modified `ContentEditableController` to account for drag mode, ensuring all children are set to `contentEditable` in block or drag modes.
- Adjusted `KeyDownController` to insert a double separator in drag mode when the caret is at the start of a row, ensuring proper row creation.
- Enhanced `selectAllText` to allow native Ctrl+A behavior in both block and drag modes, preventing selection across all blocks.

…ures

- Removed deprecated block operations: `addBlock`, `deleteBlock`, `duplicateBlock`, and `mergeBlocks`.
- Updated block-related exports to streamline functionality, focusing on drag operations.
- Refactored `splitTokensIntoBlocks` to `splitTokensIntoDragRows` for improved handling of drag-and-drop features.
- Deleted associated tests and configurations to clean up the codebase.
- Enhanced `KeyDownController` and `ContentEditableController` to better support drag mode interactions.

- Removed unused story components and consolidated the Drag stories for React and Vue.
- Updated the Markdown story to enhance clarity and maintain consistency across implementations.
- Streamlined the code by eliminating redundant components and improving overall readability.
- Ensured that the drag-and-drop functionality remains intact while simplifying the story structure.

- Replaced the previous COMPLEX_MARKDOWN with DRAG_MARKDOWN in both React and Vue Drag stories for consistency.
- Updated markdown options to streamline the rendering of drag-and-drop functionality.
- Enhanced the clarity of the Markdown story by providing a more relevant example for drag mode.

- Updated the condition in splitTokensIntoDragRows to check for trimmed content, ensuring that only non-empty tokens are processed.
- Enhanced documentation in sampleTexts to clarify the use of loose-list format for drag mode, improving understanding of the drag-and-drop functionality.