feat(wallet): paste-send confirmation step + every-time scan/upload chooser

- Pasting an invoice/address now gets the same second-step confirmation the
  scan flow has: method, destination, live balance -> amount -> balance
  after (invoice-fixed amounts win over the typed one), for every rail
  including token minting. Nothing pays until Confirm & Send.
- The scan modal opens on a chooser every time: scan with camera or
  upload/take a photo of the QR — the camera no longer auto-starts, and
  Back only relights it if camera was the user's choice.

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

neode-ui/src/components/WalletScanModal.vue

@@ -43,7 +43,22 @@
           <Transition :name="direction === 'forward' ? 'pane-forward' : 'pane-back'" mode="out-in">
             <!-- ============ SCAN PANE ============ -->
             <div v-if="pane === 'scan'" key="scan">
-              <div class="relative w-full aspect-square rounded-xl overflow-hidden bg-black/40 border border-white/10 mb-4">
+              <!-- Chooser interstitial — every open: the user picks live camera
+                   or a photo upload; neither starts until chosen. -->
+              <div v-if="scanChoice === 'unset'" class="w-full rounded-xl bg-black/30 border border-white/10 mb-4 p-6 flex flex-col items-center gap-3">
+                <svg class="w-10 h-10 text-white/40" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                  <path stroke-linecap="round" stroke-linejoin="round" stroke-width="1.5" d="M3 8V6a2 2 0 012-2h2M3 16v2a2 2 0 002 2h2m10-16h2a2 2 0 012 2v2m-4 12h2a2 2 0 002-2v-2M7 12h10" />
+                </svg>
+                <p class="text-sm text-white/60 text-center">How do you want to read the QR?</p>
+                <button v-if="!liveCameraUnavailable" @click="chooseCamera" class="glass-button w-full px-4 py-2.5 rounded-lg text-sm font-medium">
+                  Scan with camera
+                </button>
+                <button @click="photoInput?.click()" class="glass-button w-full px-4 py-2.5 rounded-lg text-sm font-medium">
+                  Upload / take a photo of the QR
+                </button>
+              </div>
+
+              <div v-else class="relative w-full aspect-square rounded-xl overflow-hidden bg-black/40 border border-white/10 mb-4">
                 <!-- opacity (not v-if/v-show): the scanner needs the element, and a
                      source-less <video> flashes a native play glyph in Android WebViews -->
                 <video ref="videoElement" class="w-full h-full object-cover transition-opacity duration-200" :class="isScanning ? 'opacity-100' : 'opacity-0'" autoplay muted playsinline></video>
@@ -73,17 +88,20 @@
                   <button @click="photoInput?.click()" class="glass-button px-4 py-2 rounded-lg text-sm font-medium">
                     Take photo of QR
                   </button>
-                  <input
-                    ref="photoInput"
-                    type="file"
-                    accept="image/*"
-                    capture="environment"
-                    class="hidden"
-                    @change="onPhotoPicked"
-                  />
                 </div>
               </div>
 
+              <!-- Single always-mounted picker input, shared by the chooser and
+                   the in-camera fallback button -->
+              <input
+                ref="photoInput"
+                type="file"
+                accept="image/*"
+                capture="environment"
+                class="hidden"
+                @change="onPhotoPicked"
+              />
+
               <div class="mb-4 p-3 bg-white/5 rounded-lg min-h-[3rem] flex items-center justify-center">
                 <p class="text-sm text-center" :class="scanStatusIsError ? 'text-red-400' : 'text-white/60'">
                   {{ scanStatus || 'Point the camera at a Lightning invoice, Bitcoin address, Cashu or Fedimint code' }}
@@ -282,7 +300,9 @@ function goBack() {
   if (pane.value === 'amount') {
     error.value = ''
     goTo('scan', 'back')
-    nextTick(() => { if (!liveCameraUnavailable.value) startScanning() })
+    // Only relight the camera when that's what the user chose; otherwise
+    // they land back on the scan/upload chooser.
+    nextTick(() => { if (scanChoice.value === 'camera' && !liveCameraUnavailable.value) startScanning() })
   } else if (pane.value === 'success') {
     close()
   }
@@ -295,6 +315,16 @@ const isScanning = ref(false)
 // open) — the fallback buttons stay hidden until it resolves, so they don't
 // flash for a second on every open.
 const autoStarting = ref(false)
+
+// Camera-vs-photo chooser, shown on EVERY open (user request 2026-07-23):
+// nothing starts until the user picks, and Back from a later pane returns to
+// the live camera only if that's what they chose.
+const scanChoice = ref<'unset' | 'camera'>('unset')
+
+function chooseCamera() {
+  scanChoice.value = 'camera'
+  void nextTick(() => startScanning())
+}
 const scanStatus = ref('')
 const scanStatusIsError = ref(false)
 const cameraError = ref(false)
@@ -709,7 +739,8 @@ function close() {
 watch(() => props.show, (open) => {
   if (open) {
     resetAll()
-    nextTick(() => { if (!liveCameraUnavailable.value) startScanning() })
+    // No auto-start: the chooser interstitial owns the first move every time.
+    scanChoice.value = 'unset'
   } else {
     stopScanning()
   }