feat(checkout): "Open in wallet" deeplink + gate LNbits-pay on having a wallet

The "Pay from my LNbits wallet" CTA was shown unconditionally — but
it only works when the customer is logged in AND has a wallet with
an admin key (both required for the POST /api/v1/payments call).
Hide it otherwise and surface a hint pointing at the new
deeplink-and-QR path instead.

Add an "Open in wallet" button next to "Copy" in OrderInvoiceCard
that navigates to `lightning:<bolt11>`. Mobile OSes route this URI
to the user's default Lightning wallet (Phoenix, Zeus, Wallet of
Satoshi, etc.), so a customer without an LNbits account can still
pay end-to-end from the same checkout surface. Even authenticated
users benefit — they may prefer their own wallet over the
LNbits-internal flow.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/modules/restaurant/components/OrderInvoiceCard.vue

@@ -5,7 +5,7 @@
  */
 import { onMounted, onUnmounted, ref, watch } from 'vue'
 import QRCode from 'qrcode'
-import { Copy, Check } from 'lucide-vue-next'
+import { Copy, Check, Zap } from 'lucide-vue-next'
 import { Button } from '@/components/ui/button'
 import { Card, CardContent } from '@/components/ui/card'
 import type { OrderInvoice } from '../types/restaurant'
@@ -58,6 +58,18 @@ function copy() {
   setTimeout(() => (copied.value = false), 1500)
 }
 
+/**
+ * The `lightning:` URI scheme is the cross-platform handoff to a
+ * native LN wallet — iOS / Android route it to whichever wallet the
+ * user has set as default (Phoenix, Zeus, Wallet of Satoshi, etc.).
+ * Desktop browsers usually no-op or prompt to pick an app; we still
+ * surface the button so mobile-web flows work end-to-end without an
+ * LNbits account.
+ */
+function openInWallet() {
+  window.location.href = `lightning:${props.invoice.bolt11}`
+}
+
 function fmtCountdown(seconds: number) {
   const m = Math.floor(seconds / 60)
   const s = seconds % 60
@@ -89,16 +101,27 @@ function fmtCountdown(seconds: number) {
           {{ Math.ceil(invoice.amount_msat / 1000) }} sat
         </span>
       </div>
+      <div class="flex gap-2">
         <Button
           variant="outline"
           size="sm"
-        class="w-full font-mono text-xs"
+          class="flex-1 font-mono text-xs"
           @click="copy"
         >
           <Check v-if="copied" class="mr-2 h-3.5 w-3.5" />
           <Copy v-else class="mr-2 h-3.5 w-3.5" />
-        {{ copied ? 'Copied' : 'Copy invoice' }}
+          {{ copied ? 'Copied' : 'Copy' }}
         </Button>
+        <Button
+          variant="default"
+          size="sm"
+          class="flex-1 text-xs"
+          @click="openInWallet"
+        >
+          <Zap class="mr-2 h-3.5 w-3.5" />
+          Open in wallet
+        </Button>
+      </div>
     </CardContent>
   </Card>
 </template>

src/modules/restaurant/views/CheckoutPage.vue

@@ -47,6 +47,7 @@ import OrderInvoiceCard from '../components/OrderInvoiceCard.vue'
 import { useCartStore } from '../stores/cart'
 import { useCheckout, type PlacedOrder } from '../composables/useCheckout'
 import { friendlyOrderStatus } from '../types/restaurant'
+import { useAuth } from '@/composables/useAuthService'
 import {
   injectService,
   tryInjectService,
@@ -60,6 +61,17 @@ const cart = useCartStore()
 const { state, placeOrders, payAll, reset } = useCheckout()
 const storage = tryInjectService<StorageService>(SERVICE_TOKENS.STORAGE_SERVICE)
 const api = injectService<RestaurantAPI>(SERVICE_TOKENS.RESTAURANT_API)
+const { user } = useAuth()
+
+// The LNbits "pay from my wallet" CTA only makes sense when the
+// customer is logged in *and* has a wallet with an admin key — both
+// are required for the POST /api/v1/payments call. Anonymous
+// customers (and logged-in users without a wallet) still get the QR
+// + "Open in wallet" deeplink in OrderInvoiceCard, which routes to a
+// native LN wallet on mobile.
+const canPayFromLnbits = computed(
+  () => !!user.value?.wallets?.[0]?.adminkey
+)
 
 // ----------------------------------------------------------------- //
 // review phase                                                       //
@@ -427,7 +439,7 @@ function buildOrderInvoice(p: PlacedOrder) {
         </Alert>
 
         <Button
-          v-if="!allPaid"
+          v-if="!allPaid && canPayFromLnbits"
           size="lg"
           class="w-full"
           :disabled="isPaying"
@@ -438,6 +450,14 @@ function buildOrderInvoice(p: PlacedOrder) {
           Pay from my LNbits wallet
         </Button>
 
+        <p
+          v-else-if="!allPaid"
+          class="text-center text-xs text-muted-foreground"
+        >
+          Use the "Open in wallet" button above to pay with any
+          Lightning wallet on your phone, or scan the QR.
+        </p>
+
         <Button
           v-if="!allPaid"
           variant="ghost"