Offer a new share as a QR code and through the share sheet

The share created page gets "Show QR code", a dialog with the link as a
QR code (black on white, full screen on a phone) that downloads as a PNG
drawn in the browser, with a password reminder for protected shares; and
"Share…", which opens the device's share sheet where there is one. Both
carry only the link.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V9NnLxnPp8vaaurb3Z1MFy

README.md

@@ -5,7 +5,7 @@ A simple, self-hosted file sharing solution built with Laravel. Upload files, ge
 ## Features
 
 - **File Uploading** — Drag & drop or browse to upload single/multiple files and folders with real-time progress
-- **Shareable Links** — Each upload generates a unique link for recipients
+- **Shareable Links** — Each upload generates a unique link for recipients, also as a QR code (saved as a PNG) or through the device's share sheet
 - **End-to-End Encryption** — All files encrypted at rest using AES-256-GCM (chunked, streaming)
 - **Password Protection** — Optionally protect shares with a password
 - **Expiration** — Shares auto-expire after a configurable duration (1 hour to 30 days)