New files:
- web/src/hooks/useFileUpload.ts: presigned upload hook that gets
a presigned PUT URL from POST /api/uploads/presign then uploads
via XMLHttpRequest for progress tracking
- web/src/components/items/FileDropZone.tsx: drag-and-drop file
upload zone with file list, type-colored badges (CAD/PDF/IMG),
progress bars, and remove buttons
Features:
- Dashed border drop zone with drag-over visual feedback
- Click to browse or drag files to add
- File type detection by extension with colored badges
- Upload progress bar (2px mauve) during active uploads
- Error state display per file
- Configurable accepted file types via accept prop
Closes#14
3358e7dd1c