接入移动端原生扫码能力

新增 scanner.scanQrCode HostBridge 契约与二维码结果归一。

接入 Expo Camera 扫码 overlay 并保留 H5 浏览器扫码回退。

让 Tauri 白名单识别扫码 method 但不声明桌面扫码能力。

同步原生壳门禁、Expo 权限检查、方案文档和共享决策记录。

src/components/platform-entry/PlatformProfileQrScannerModal.tsx

@@ -16,6 +16,7 @@ type BarcodeDetectorConstructorLike = new (options?: {
 
 export type PlatformProfileQrScannerModalProps = {
   error: string | null;
+  mode?: 'camera' | 'resultOnly';
   result: string | null;
   onClose: () => void;
   onError: (message: string) => void;
@@ -37,6 +38,7 @@ function getBarcodeDetectorConstructor(): BarcodeDetectorConstructorLike | null
  */
 export function PlatformProfileQrScannerModal({
   error,
+  mode = 'camera',
   result,
   onClose,
   onError,
@@ -47,7 +49,7 @@ export function PlatformProfileQrScannerModal({
 
   useEffect(() => {
     const videoElement = videoRef.current;
-    if (!videoElement) {
+    if (!videoElement || mode === 'resultOnly') {
       return;
     }
 
@@ -141,7 +143,7 @@ export function PlatformProfileQrScannerModal({
       clearScanTimer();
       stopCamera();
     };
-  }, [onError, onResult]);
+  }, [mode, onError, onResult]);
 
   return (
     <PlatformProfileModalShell
@@ -162,15 +164,17 @@ export function PlatformProfileQrScannerModal({
         />
       </div>
       <div className="space-y-3 px-5 py-5">
-        <div className="platform-qr-scanner-modal__viewport">
-          <video
-            ref={videoRef}
-            className="h-full w-full object-cover"
-            playsInline
-            muted
-          />
-          <span className="platform-qr-scanner-modal__frame" />
-        </div>
+        {mode === 'camera' ? (
+          <div className="platform-qr-scanner-modal__viewport">
+            <video
+              ref={videoRef}
+              className="h-full w-full object-cover"
+              playsInline
+              muted
+            />
+            <span className="platform-qr-scanner-modal__frame" />
+          </div>
+        ) : null}
         {result ? (
           <PlatformStatusMessage
             tone="success"