fix(wallet): photo QR decode uses native BarcodeDetector first — dense Lightning invoices scan reliably

On the companion (plain-http LAN = no secure context = no live camera)
the photo path IS the scanner, and qr-scanner's single wasm pass often
misses the dense QR of a full BOLT11 invoice. Android WebView's native
BarcodeDetector handles them easily — try it first, wasm as fallback,
plus a 'Reading photo…' status.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/components/WalletScanModal.vue

@@ -363,9 +363,10 @@ async function onPhotoPicked(e: Event) {
   const input = e.target as HTMLInputElement
   const file = input.files?.[0]
   if (!file) return
+  scanStatusIsError.value = false
+  scanStatus.value = 'Reading photo…'
   try {
-    const result = await QrScanner.scanImage(file, { returnDetailedScanResult: true })
-    handleScanned(result.data)
+    handleScanned(await decodePhotoRobust(file))
   } catch {
     scanStatusIsError.value = true
     scanStatus.value = 'No QR code found in that photo — try again, closer and well-lit'
@@ -374,6 +375,28 @@ async function onPhotoPicked(e: Event) {
   }
 }
 
+/** Decode a QR photo with every engine we have. On the companion app the
+ *  photo path IS the scan path (plain-http LAN = no secure context = no
+ *  live camera), and Lightning invoices make DENSE codes that the wasm
+ *  engine's single pass often misses (reported 2026-07-22: "camera not
+ *  picking up the invoice"). Android WebView's native BarcodeDetector is
+ *  far stronger on dense codes, so try it first; fall back to qr-scanner. */
+async function decodePhotoRobust(file: File): Promise<string> {
+  try {
+    const Detector = (window as unknown as { BarcodeDetector?: new (opts: { formats: string[] }) => { detect(src: ImageBitmap): Promise<Array<{ rawValue: string }>> } }).BarcodeDetector
+    if (Detector) {
+      const bmp = await createImageBitmap(file)
+      const codes = await new Detector({ formats: ['qr_code'] }).detect(bmp)
+      const hit = codes.find(c => c.rawValue)
+      if (hit) return hit.rawValue
+    }
+  } catch {
+    // Native detector unavailable/failed — wasm engine below.
+  }
+  const result = await QrScanner.scanImage(file, { returnDetailedScanResult: true })
+  return result.data
+}
+
 // --- Detection (ported from k484's scanner) ---
 const rail = ref<Rail>('lightning')
 const action = ref<Action>('pay-invoice')