Fix Scanner: remove scanner.clear() that destroyed camera element

scanner.clear() removes the video element entirely, preventing restart.
Only use stop() + DOM child cleanup before creating new instance.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: JiroMusik

src/pages/Scanner.tsx

@@ -86,7 +86,6 @@ export default function Scanner() {
       clearTimeout(timer);
       if (scanner) {
         try { if (scanner.isScanning) scanner.stop().catch(() => {}); } catch {}
-        try { scanner.clear(); } catch {}
       }
       html5ScannerRef.current = null;
     };
@@ -273,7 +272,6 @@ export default function Scanner() {
     const scanner = html5ScannerRef.current;
     if (scanner) {
       try { if (scanner.isScanning) scanner.stop().catch(() => {}); } catch {}
-      try { scanner.clear(); } catch {}
       html5ScannerRef.current = null;
     }
     setImage(null);