Replace the tree-filtered search with a flat list that shows icon + name
on the left and parent path on the right, matching the Figma design.
Clicking a file opens its tab; clicking a folder clears the search and
reveals the folder in the tree.
Implement unified drag system that supports both internal node moves
and external file uploads with consistent UI feedback. Uses native
HTML5 drag API with shared visual states (isDragOver, isBlinking,
DragActionTooltip showing 'Move to' or 'Upload to').
- Add constants.ts with ROOT_ID, CONTEXT_MENU_TYPE, NODE_MENU_TYPE
- Add root utilities to tree-utils.ts (isRootId, toApiParentId, etc.)
- Replace '__root__' with ROOT_ID for consistent root identifier
- Replace inline 'blank'/'root' strings with constants
- Use NodeMenuType for type-safe menu type props
- Remove duplicate ContextMenuType from types.ts, use from constants.ts
- Extract useFileOperations hook to hooks/use-file-operations.ts
- Move tree utilities to utils/tree-utils.ts
- Move file utilities to utils/file-utils.ts (renamed from utils.ts)
- Remove unnecessary JSDoc comments throughout components
- Simplify type.ts to only contain local type definitions
- Clean up store/index.ts by removing verbose comments
