Can I build my own Dropbox with AI?

Build a simple private file vault similar to a lightweight Dropbox for personal or client use.

**Objective:** Let a logged-in user upload files into folders, browse them, and share selected files via temporary download links.

**Target user:** A freelancer or small business that needs a branded place to store and share files without desktop sync.

**Core functionality:**
- Create folders and nest them one level deep
- Upload files (images, PDFs, docs) to a folder
- List files with name, size, and upload date
- Rename, move, and delete files
- Generate a shareable download link (optional expiry)
- Show basic storage usage

**Pages/screens:**
- Login
- Folder browser / file list
- Upload modal or drag-and-drop zone
- File detail (preview if image/PDF, share link controls)
- Settings: account and storage usage

**User flows:**
1. User logs in and opens a folder
2. User uploads files via drag-and-drop
3. User creates a share link for a client deliverable
4. Client opens link and downloads (no account required)
5. User revokes the share link when done

**UI direction:** Clean file-manager aesthetic, folder sidebar, dense but readable file rows, clear drag-and-drop target. No marketing chrome.

**Data model:**
- User: { id, email, name }
- Folder: { id, userId, parentId?, name }
- File: { id, userId, folderId, name, storageKey, size, mimeType, createdAt }
- ShareLink: { id, fileId, token, expiresAt?, revoked }

**Authentication:** Email/password or magic link for vault owners. Share links are public until revoked.

**APIs/integrations:** Object storage for file bytes (S3-compatible or builder-native storage).

**Responsive requirements:** Upload and browse must work on mobile browsers.

**Error states:** Failed uploads with retry; expired/revoked share links show a friendly message; oversized files rejected with a clear limit.

**Explicit exclusions:** No desktop sync client, no selective sync, no real-time co-editing, no Dropbox Paper, no team org charts in v1.

**Suggested implementation order:**
1. Auth + folder/file schema
2. Upload to object storage + file list
3. Rename / move / delete
4. Share links with expiry
5. Storage usage and polish