File uploads

Build Racecamp's file uploads: dropzone, per-file progress with pending/processing/ready/
failed + retry states, existing files list with thumbnails and sizes. Nitro Kit
Dropzone and Table, dummy files.

Make bringing files in feel effortless. Build the file upload area for Racecamp, a
project management app from 27 Seagulls: a dropzone for drag-and-drop, real upload
states per file
— pending, processing, ready, and failed with a retry — and an existing-files list with
thumbnails, sizes, and sharing.

Uploads never touch the app server directly; progress and statuses stay per-file. This
is a UI showcase — dummy files and states, nothing really uploads. Use Nitro Kit
components throughout.