feat(activities): provider-aware checkout labels and conversion preview

The buyer-side payment-method block now surfaces one button per
configured fiat provider — Stripe, PayPal, Square, SEPA — rather than
a single bare "Fiat" catch-all. Buttons read in provider names so the
buyer never has to guess what rail backs each choice; the dispatch on
click forwards both `rail` and `provider` to the existing
`ticketApi.requestTicket` signature.

PaymentMethodSelector + useFiatProviders from the base module drive
the list. The Lightning button picks up a "≈ N sats" badge whenever
the event price is denominated in fiat, so the buyer sees the live
sat charge alongside the headline price. A new conversion-preview
line under the headline shows the sat→fiat estimate in the inverse
case (sat-denominated event with fiat enabled), giving the rail-vs-
unit asymmetry an explicit place in the UI.

Explanatory copy makes the equivalence explicit: both methods charge
the same amount, rates are estimates, exact amount locks in at
checkout.

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

src/modules/activities/components/PurchaseTicketDialog.vue

@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { computed, onUnmounted, ref } from 'vue'
+import { computed, onUnmounted, ref, watch } from 'vue'
 import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogDescription } from '@/components/ui/dialog'
 import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
@@ -7,9 +7,14 @@ import { useTicketPurchase } from '../composables/useTicketPurchase'
 import { useAuth } from '@/composables/useAuthService'
 import { injectService, SERVICE_TOKENS } from '@/core/di-container'
 import type { TicketApiService } from '../services/TicketApiService'
-import type { PaymentMethod } from '../types/ticket'
+import { User, Wallet, CreditCard, Zap, Ticket, ExternalLink, Landmark } from 'lucide-vue-next'
-import { User, Wallet, CreditCard, Zap, Ticket, ExternalLink } from 'lucide-vue-next'
 import { formatEventPrice, formatWalletBalance } from '@/lib/utils/formatting'
+import PaymentMethodSelector, {
+  type PaymentMethod as PaymentMethodEntry,
+} from '@/modules/base/components/payments/PaymentMethodSelector.vue'
+import PriceConversionPreview from '@/modules/base/components/payments/PriceConversionPreview.vue'
+import { useFiatProviders } from '@/modules/base/composables/useFiatProviders'
+import { usePriceConversion } from '@/modules/base/composables/usePriceConversion'
 
 interface Props {
   event: {
@@ -51,7 +56,10 @@ const {
   showTicketQR
 } = useTicketPurchase()
 
-const paymentMethod = ref<PaymentMethod>('lightning')
+const { providers, providerMeta } = useFiatProviders()
+const { convert } = usePriceConversion()
+
+const selectedMethodId = ref<string>('lightning')
 const fiatRedirectUrl = ref<string | null>(null)
 const fiatProviderLabel = ref<string | null>(null)
 const isFiatPending = ref(false)
@@ -59,12 +67,85 @@ const fiatError = ref<string | null>(null)
 
 const canChooseFiat = computed(() => Boolean(props.event.allow_fiat))
 
+// Lightning-button badge: when the price is denominated in fiat, show
+// the live sat equivalent so the buyer knows roughly what their wallet
+// will be charged. Best-effort — silent if the conversion fails.
+const lightningSats = ref<number | null>(null)
+watch(
+  () => [props.event.currency, props.event.price_per_ticket, props.isOpen] as const,
+  async ([cur, amt, open]) => {
+    if (!open || cur === 'sat' || !amt) {
+      lightningSats.value = null
+      return
+    }
+    lightningSats.value = await convert(amt as number, cur as string, 'sat')
+  },
+  { immediate: true },
+)
+
+function iconFor(hint: 'card' | 'bank' | 'wallet') {
+  if (hint === 'bank') return Landmark
+  if (hint === 'wallet') return Wallet
+  return CreditCard
+}
+
+const paymentMethods = computed<PaymentMethodEntry[]>(() => {
+  const lightning: PaymentMethodEntry = {
+    id: 'lightning',
+    rail: 'lightning',
+    label: 'Lightning',
+    icon: Zap,
+    available: true,
+    badge:
+      props.event.currency !== 'sat' && lightningSats.value
+        ? `≈ ${Math.round(lightningSats.value).toLocaleString()} sats`
+        : undefined,
+  }
+  if (!props.event.allow_fiat) return [lightning]
+
+  if (providers.value.length > 0) {
+    const fiatRails: PaymentMethodEntry[] = providers.value.map((id) => {
+      const meta = providerMeta(id)
+      return {
+        id: `fiat:${id}`,
+        rail: 'fiat',
+        provider: id,
+        label: meta.label,
+        icon: iconFor(meta.icon),
+        available: true,
+      }
+    })
+    return [lightning, ...fiatRails]
+  }
+
+  // Degenerate fallback — allow_fiat is on but the buyer's session
+  // can't enumerate the organizer's providers. Show a generic Card
+  // button and let the backend pick a default at request time.
+  return [
+    lightning,
+    {
+      id: 'fiat',
+      rail: 'fiat',
+      label: 'Card',
+      icon: CreditCard,
+      available: true,
+    },
+  ]
+})
+
+const selectedMethod = computed(() =>
+  paymentMethods.value.find((m) => m.id === selectedMethodId.value) ?? paymentMethods.value[0],
+)
+
 async function handlePurchase() {
   if (!canPurchase.value) return
   fiatError.value = null
 
+  const method = selectedMethod.value
+  if (!method) return
+
   // Lightning path: existing composable handles QR + wallet auto-pay.
-  if (paymentMethod.value === 'lightning') {
+  if (method.rail === 'lightning') {
     try {
       await purchaseTicketForEvent(props.event.id)
     } catch (err) {
@@ -74,9 +155,10 @@ async function handlePurchase() {
   }
 
   // Fiat path: composable can't drive it (no QR / no bolt11). Hit the
-  // API directly, then redirect the buyer to the provider's checkout
+  // API directly with the chosen provider, then redirect the buyer to
-  // URL. Payment confirmation happens via webhook on the backend and
+  // the provider's checkout URL. Payment confirmation happens via
-  // shows up next time the buyer reloads MyTickets.
+  // webhook on the backend and shows up next time the buyer reloads
+  // MyTickets.
   try {
     isFiatPending.value = true
     const lnbitsAPI = injectService(SERVICE_TOKENS.LNBITS_API) as any
@@ -92,14 +174,16 @@ async function handlePurchase() {
       props.event.id,
       userId,
       accessToken,
-      { paymentMethod: 'fiat' },
+      { paymentMethod: 'fiat', fiatProvider: method.provider },
     )
     if (!invoice.isFiat || !invoice.fiatPaymentRequest) {
       fiatError.value = 'Fiat provider did not return a checkout URL.'
       return
     }
     fiatRedirectUrl.value = invoice.fiatPaymentRequest
-    fiatProviderLabel.value = invoice.fiatProvider ?? 'provider'
+    fiatProviderLabel.value = invoice.fiatProvider
+      ? providerMeta(invoice.fiatProvider).label
+      : method.label
   } catch (err) {
     fiatError.value = err instanceof Error ? err.message : 'Fiat checkout failed'
   } finally {
@@ -115,7 +199,7 @@ function openFiatCheckout() {
 function handleClose() {
   emit('update:isOpen', false)
   resetPaymentState()
-  paymentMethod.value = 'lightning'
+  selectedMethodId.value = 'lightning'
   fiatRedirectUrl.value = null
   fiatProviderLabel.value = null
   fiatError.value = null
@@ -219,34 +303,35 @@ onUnmounted(() => {
               <span class="text-sm text-muted-foreground">Price:</span>
               <span class="text-sm font-medium">{{ formatEventPrice(event.price_per_ticket, event.currency) }}</span>
             </div>
+            <PriceConversionPreview
+              v-if="canChooseFiat && event.currency === 'sat' && event.fiat_currency"
+              :amount="event.price_per_ticket"
+              from="sat"
+              :to="event.fiat_currency"
+              prefix="Equivalent ~"
+              suffix=" if paid in fiat"
+            />
           </div>
         </div>
 
         <!-- Payment method selector (only shown when fiat is enabled
-             on the event). Hidden entirely for Lightning-only events
+             on the event). Buttons surface one per configured fiat
-             to keep the dialog uncluttered. -->
+             provider so "Stripe" / "PayPal" / "Square" stand alongside
+             Lightning rather than collapsing into a single "Fiat"
+             catch-all. Hidden entirely for Lightning-only events to
+             keep the dialog uncluttered. -->
         <div v-if="canChooseFiat" class="bg-muted/50 rounded-lg p-4 space-y-2">
           <div class="text-sm font-medium">Payment method</div>
-          <div class="grid grid-cols-2 gap-2">
+          <p class="text-xs text-muted-foreground">
-            <Button
+            Both methods charge the same amount via different rails.
-              type="button"
+            Live rates shown are estimates; the exact sat amount locks
-              :variant="paymentMethod === 'lightning' ? 'default' : 'outline'"
+            in when you start checkout.
-              size="sm"
+          </p>
-              @click="paymentMethod = 'lightning'"
+          <PaymentMethodSelector
-            >
+            :methods="paymentMethods"
-              <Zap class="w-4 h-4 mr-1.5" />
+            :model-value="selectedMethodId"
-              Lightning
+            @update:model-value="selectedMethodId = $event"
-            </Button>
+          />
-            <Button
-              type="button"
-              :variant="paymentMethod === 'fiat' ? 'default' : 'outline'"
-              size="sm"
-              @click="paymentMethod = 'fiat'"
-            >
-              <CreditCard class="w-4 h-4 mr-1.5" />
-              {{ event.fiat_currency ?? 'Fiat' }}
-            </Button>
-          </div>
         </div>
 
         <div v-if="error || fiatError" class="text-sm text-destructive bg-destructive/10 p-3 rounded-lg">
@@ -272,13 +357,13 @@ onUnmounted(() => {
         <Button
           v-else
           @click="handlePurchase"
-          :disabled="isLoading || isFiatPending || (paymentMethod === 'lightning' && !canPurchase)"
+          :disabled="isLoading || isFiatPending || (selectedMethod?.rail === 'lightning' && !canPurchase)"
           class="w-full"
         >
           <span v-if="isLoading || isFiatPending" class="animate-spin mr-2">⚡</span>
-          <span v-else-if="paymentMethod === 'fiat'" class="flex items-center gap-2">
+          <span v-else-if="selectedMethod?.rail === 'fiat'" class="flex items-center gap-2">
             <CreditCard class="w-4 h-4" />
-            Continue to {{ event.fiat_currency ?? 'fiat' }} checkout
+            Continue to {{ selectedMethod.label }} checkout
           </span>
           <span v-else-if="hasWalletWithBalance" class="flex items-center gap-2">
             <Zap class="w-4 h-4" />