feat(activities): notification config on event create + edit

CreateEventDialog gains a collapsible "Buyer notifications" section
exposing the EventExtra fields added upstream in v1.4.0 / v1.6.0:

- email_notifications + nostr_notifications switches — opt buyers
  into email and NIP-04 Nostr DM ticket confirmations.
- notification_subject + notification_body inputs — let organizers
  customize the message. Empty falls back to extension defaults.

Submit handler builds `extra` by overlaying onto the existing
event.extra so unrelated fields the LNbits admin UI sets
(promo_codes, conditional, min_tickets) survive the round-trip
through the webapp. Populate-from-event mirrors the same.

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

src/modules/activities/components/CreateEventDialog.vue

@@ -24,6 +24,9 @@ import { Input } from '@/components/ui/input'
 import { Textarea } from '@/components/ui/textarea'
 import { Button } from '@/components/ui/button'
 import { Badge } from '@/components/ui/badge'
+import { Switch } from '@/components/ui/switch'
+import { Collapsible, CollapsibleContent, CollapsibleTrigger } from '@/components/ui/collapsible'
+import { Bell, ChevronDown } from 'lucide-vue-next'
 import { ScrollArea } from '@/components/ui/scroll-area'
 import {
   Select,
@@ -122,6 +125,10 @@ const formSchema = toTypedSchema(
       currency: z.string().default("sat"),
       amount_tickets: z.number().min(0).max(100000).default(0),
       price_per_ticket: z.number().min(0).default(0),
+      email_notifications: z.boolean().default(false),
+      nostr_notifications: z.boolean().default(false),
+      notification_subject: z.string().max(200).default(''),
+      notification_body: z.string().max(2000).default(''),
     })
     .superRefine((v, ctx) => {
       // End must not precede start. Compare on the folded date+time
@@ -152,6 +159,10 @@ const form = useForm({
     currency: 'sat',
     amount_tickets: 0,
     price_per_ticket: 0,
+    email_notifications: false,
+    nostr_notifications: false,
+    notification_subject: '',
+    notification_body: '',
   }
 })
 
@@ -174,6 +185,7 @@ function splitDateTime(value: string | null | undefined): { date: string; time:
 // When `true`, suppress the auto-mirror watcher so we don't clobber an
 // edit-mode population with start-date side effects mid-setValues.
 const isPopulating = ref(false)
+const notificationsOpen = ref(false)
 
 // Auto-mirror end date to start: when the user picks a start date,
 // surface that same date in the end-date picker so a one-day event
@@ -215,6 +227,10 @@ async function populateFromEvent(event: TicketedEvent) {
     currency: event.currency ?? 'sat',
     amount_tickets: event.amount_tickets ?? 0,
     price_per_ticket: event.price_per_ticket ?? 0,
+    email_notifications: event.extra?.email_notifications ?? false,
+    nostr_notifications: event.extra?.nostr_notifications ?? false,
+    notification_subject: event.extra?.notification_subject ?? '',
+    notification_body: event.extra?.notification_body ?? '',
   })
   selectedCategories.value = [...(event.categories ?? [])]
   if (event.banner) {
@@ -322,6 +338,18 @@ const onSubmit = form.handleSubmit(async (formValues) => {
     if (formValues.price_per_ticket) eventData.price_per_ticket = formValues.price_per_ticket
     if (selectedCategories.value.length > 0) eventData.categories = selectedCategories.value
 
+    // Notification config goes inside the `extra` envelope. On edit
+    // overlay onto the existing event.extra so unrelated fields the
+    // LNbits admin UI sets (promo_codes, conditional, min_tickets)
+    // survive the round-trip.
+    eventData.extra = {
+      ...(props.event?.extra ?? {}),
+      email_notifications: formValues.email_notifications,
+      nostr_notifications: formValues.nostr_notifications,
+      notification_subject: formValues.notification_subject,
+      notification_body: formValues.notification_body,
+    }
+
     if (isEditMode.value) {
       if (!props.onUpdateEvent || !props.event?.id) {
         toastService.error('Update handler missing')
@@ -591,6 +619,68 @@ const handleOpenChange = (open: boolean) => {
             </FormField>
           </div>
 
+          <!-- Ticket buyer notifications (collapsible). The backend
+               sends email + NIP-04 Nostr DM confirmations on
+               payment when these are on. notification_subject /
+               body let the organizer customize the message; empty
+               strings fall back to the extension's defaults. -->
+          <Collapsible v-model:open="notificationsOpen">
+            <CollapsibleTrigger as-child>
+              <Button type="button" variant="ghost" size="sm" class="w-full justify-between text-muted-foreground">
+                <span class="flex items-center gap-1.5">
+                  <Bell class="w-4 h-4" />
+                  Buyer notifications
+                </span>
+                <ChevronDown class="w-4 h-4 transition-transform" :class="{ 'rotate-180': notificationsOpen }" />
+              </Button>
+            </CollapsibleTrigger>
+            <CollapsibleContent class="space-y-3 pt-2">
+              <div class="grid grid-cols-1 sm:grid-cols-2 gap-3">
+                <FormField v-slot="{ value, handleChange }" name="email_notifications">
+                  <FormItem class="flex flex-row items-center justify-between rounded-md border p-3">
+                    <FormLabel class="text-sm">Email confirmation</FormLabel>
+                    <FormControl>
+                      <Switch :model-value="value as boolean" @update:model-value="handleChange" />
+                    </FormControl>
+                  </FormItem>
+                </FormField>
+
+                <FormField v-slot="{ value, handleChange }" name="nostr_notifications">
+                  <FormItem class="flex flex-row items-center justify-between rounded-md border p-3">
+                    <FormLabel class="text-sm">Nostr DM confirmation</FormLabel>
+                    <FormControl>
+                      <Switch :model-value="value as boolean" @update:model-value="handleChange" />
+                    </FormControl>
+                  </FormItem>
+                </FormField>
+              </div>
+
+              <FormField v-slot="{ componentField }" name="notification_subject">
+                <FormItem>
+                  <FormLabel class="text-sm">Subject</FormLabel>
+                  <FormControl>
+                    <Input placeholder="Your ticket for {event_name}" v-bind="componentField" />
+                  </FormControl>
+                  <FormDescription class="text-xs">Leave blank to use the default.</FormDescription>
+                  <FormMessage />
+                </FormItem>
+              </FormField>
+
+              <FormField v-slot="{ componentField }" name="notification_body">
+                <FormItem>
+                  <FormLabel class="text-sm">Body</FormLabel>
+                  <FormControl>
+                    <Textarea placeholder="See you there!" rows="3" v-bind="componentField" />
+                  </FormControl>
+                  <FormDescription class="text-xs">
+                    Leave blank to use the default. The ticket link is appended automatically.
+                  </FormDescription>
+                  <FormMessage />
+                </FormItem>
+              </FormField>
+            </CollapsibleContent>
+          </Collapsible>
+
           <!-- Actions -->
           <div class="flex justify-end gap-3 pt-2">
             <Button type="button" variant="outline" @click="handleOpenChange(false)" :disabled="isLoading">