feat: add event approval workflow with admin UI

Non-admin event submissions now land in a "proposed" queue that LNbits
admins review before the event becomes ticketable and publicly listed.

- m008 adds events.events.status (proposed/approved/rejected); m010 seeds
  an events.settings singleton row with the auto_approve toggle.
- Models: Event/CreateEvent.status, EventsSettings, optional date fields
  with sensible defaults (closing_date defaults to event_end_date which
  defaults to event_start_date), PublicEvent.status surfaces the workflow
  state on the public endpoint.
- crud: get_all/public/pending_events for the admin views; get/update_settings
  for the auto_approve toggle; create_event auto-fills missing date defaults.
- views_api:
  * POST /api/v1/events accepts wallet invoice keys so anyone can submit;
    handler stamps status="proposed" for non-admins when auto_approve is off
  * /public, /all, /pending, /settings (GET+PUT), /{id}/{approve,reject},
    /{id}/tickets endpoints; literal-prefix routes declared before /{event_id}
    so FastAPI matches them correctly
  * Public GET /{event_id} bypasses sold-out / closing-window gates for
    proposed/rejected events and returns the trimmed PublicEvent so the SFC
    can render a "pending approval" banner
  * POST /tickets/{event_id} rejects when event.status != "approved"
- Frontend: index.vue gains an admin Settings card, Pending Approvals list,
  status badge column and approve/reject row actions, plus an All Users'
  Events admin table; index.js gains the data + methods + an isAdmin probe
  via GET /events/all; display.vue shows pending/rejected banners and
  hides the Buy Ticket form unless status === "approved".

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

static/js/display.vue

@@ -12,7 +12,32 @@
           <div v-html="event.info" class="q-pa-lg"></div>
         </q-card-section>
       </q-card>
-      <q-card class="q-pa-lg">
+
+      <q-banner
+        v-if="event.status === 'proposed'"
+        class="bg-orange-2 text-orange-10"
+        rounded
+      >
+        <template v-slot:avatar>
+          <q-icon name="pending" color="orange-10"></q-icon>
+        </template>
+        <span class="text-weight-medium">Pending approval</span> &mdash; this
+        event is awaiting an admin review and is not yet open for tickets.
+      </q-banner>
+
+      <q-banner
+        v-else-if="event.status === 'rejected'"
+        class="bg-red-2 text-red-10"
+        rounded
+      >
+        <template v-slot:avatar>
+          <q-icon name="block" color="red-10"></q-icon>
+        </template>
+        <span class="text-weight-medium">Not approved</span> &mdash; this event
+        was reviewed and is not being published.
+      </q-banner>
+
+      <q-card v-if="event.status === 'approved'" class="q-pa-lg">
         <q-card-section class="q-pa-none">
           <h5 class="q-mt-none">Buy Ticket</h5>
           <q-form @submit="createInvoice()" class="q-gutter-md">