17bd50cc4e
B2 of the Matrix protocol-gaps roadmap, gate-green (688 tests): - Enable QR verification methods (show/scan/reciprocate) in initMatrix. - Extend DeviceVerification: the Ready step offers your own QR (byte-mode encode via qrcode), a camera 'Scan their QR code' flow, and an emoji fallback; the Started step routes reciprocate → a confirm step (useVerifierShowReciprocateQr) or SAS as before. - New QrScanner component: getUserMedia + jsQR, handing the raw binaryData bytes to request.scanQRCode (BarcodeDetector is string-only, so can't be used). - Adds qrcode + jsqr (small, pure-JS, client-only); build-verified under rolldown. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>