feat: QR code for sharing results — scan to see speed on your phone

[ajithakdev]

Summary

Generate a QR code in the popup that links to the shareable result URL, so users can scan it with their phone to see or share the result.

Use case

• User runs a test on their laptop
• Wants to show ISP support agent on the phone
• Clicks "QR" button → QR code appears in popup
• Scans with phone → opens result page on phone
• Shares directly from phone to WhatsApp, email, etc.

Why

• QR sharing is natural in India (UPI payments trained everyone to scan QR codes)
• Bridges desktop extension to mobile sharing seamlessly
• Unique — no speed test extension has this
• Tiny implementation (QR generation is ~3KB library)

Implementation

• Use lightweight QR library (qrcode-generator, ~3KB minified)
• Generate QR for the existing buildShareUrl() output
• Display in popup via Canvas element
• Add "QR" button next to existing Share button