Scan: throttled Erfolgs-Log + sichtbare Decode-Fehler statt stillem catch

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app.js

@@ -135,6 +135,12 @@
     const c = $(canvasId);
     const ctx = c.getContext('2d', { willReadFrequently: true });
     let lastScan = 0;
+    let lastLog = 0;
+    const logThrottled = (now, msg) => {
+      if (now - lastLog < 1000) return;
+      lastLog = now;
+      addPairingLog(msg);
+    };
 
     const detect = barcodeDetector
       ? async () => {
@@ -153,13 +159,20 @@
       if (!v.videoWidth) { camRaf = requestAnimationFrame(tick); return; }
       if (now - lastScan < 100) { camRaf = requestAnimationFrame(tick); return; }
       lastScan = now;
+      let raw = null;
       try {
-        const raw = await detect();
+        raw = await detect();
         if (raw) {
           const p = await unpack(raw);
-          if (p.v === 1) { callback(p, raw); return; }
+          if (p.v === 1) {
+            logThrottled(now, 'QR gescannt ✓');
+            callback(p, raw);
+            return;
+          }
+        }
+      } catch (e) {
+        if (raw) logThrottled(now, `QR gescannt, aber ungültige Daten: ${e.message}`);
       }
-      } catch (_) {}
       camRaf = requestAnimationFrame(tick);
     });
   }