WIP: Unified contact QR code display + capture

src/services/QRScanner/QRScannerService.ts

@@ -0,0 +1,17 @@
+import { EventEmitter } from "events";
+
+export interface QRScannerListener {
+  onScan: (result: string) => void;
+  onError: (error: Error) => void;
+}
+
+export interface QRScannerService {
+  checkPermissions(): Promise<boolean>;
+  requestPermissions(): Promise<boolean>;
+  isSupported(): Promise<boolean>;
+  startScan(): Promise<void>;
+  stopScan(): Promise<void>;
+  addListener(listener: QRScannerListener): void;
+  cleanup(): Promise<void>;
+  onStream(callback: (stream: MediaStream | null) => void): void;
+}