feat(scheduling): calendar_failed badge + admin "retry now" action

Surface pending/calendar_failed booking states in the admin bookings list with
proper status badges (failed shows the last calendar error as a tooltip), and
add an operator "Retry now" action. The retry re-drives the same Stalwart
calendar write (confirm + attendee email on success); for a terminal
calendar_failed booking it re-claims the slot lock atomically first and refuses
if the time was taken in the meantime, so a manual retry can never double-book.

apps/portal/pages/admin/scheduling.vue

@@ -42,6 +42,7 @@ interface Booking {
   attendeeName: string
   attendeeEmail: string
   eventTypeId: string
+  lastCalendarError?: string
 }
 
 const toast = useToast()
@@ -323,6 +324,31 @@ function cancelBookingAdmin(b: Booking) {
   })
 }
 
+// Badge tone for a booking status (Badge supports ok/warn/bad/neutral).
+function bookingTone(status: string): 'ok' | 'warn' | 'bad' | 'neutral' {
+  if (status === 'confirmed') return 'ok'
+  if (status === 'pending') return 'warn'
+  if (status === 'calendar_failed') return 'bad'
+  return 'neutral'
+}
+
+// "Retry now" — re-drive the Stalwart calendar write for a pending /
+// calendar_failed booking. On success it confirms + emails the attendee.
+const retryingId = ref<string | null>(null)
+async function retryBookingAdmin(b: Booking) {
+  retryingId.value = b._id
+  try {
+    const updated = (await request(`${base.value}/bookings/${b._id}/retry`, { method: 'POST' })) as Booking
+    toast.ok(updated.status === 'confirmed' ? 'Booking confirmed' : 'Retry queued', updated.status === 'confirmed' ? 'The calendar event was written and the attendee emailed.' : 'The calendar write failed again; the background worker will keep retrying.')
+    await loadHostData()
+    await loadOverview()
+  } catch (err) {
+    toastErr(err, 'Retry failed')
+  } finally {
+    retryingId.value = null
+  }
+}
+
 // ── Create event type ──
 const etOpen = ref(false)
 const etBusy = ref(false)
@@ -751,9 +777,15 @@ const maskSecret = (s: string) => (s.length > 12 ? `${s.slice(0, 9)}…${s.slice
                   <div class="mute small">{{ fmtDateTime(b.startUtc) }} – {{ fmtDateTime(b.endUtc) }}</div>
                 </div>
                 <div class="itemactions">
-                  <Badge :tone="b.status === 'confirmed' ? 'ok' : b.status === 'cancelled' ? 'bad' : 'neutral'">{{ b.status }}</Badge>
+                  <Badge :tone="bookingTone(b.status)" :title="b.lastCalendarError || undefined">{{ statusLabel[b.status] ?? b.status }}</Badge>
                   <UiButton v-if="b.status === 'confirmed'" variant="ghost" @click="openReschedule(b)">Reschedule</UiButton>
                   <UiButton v-if="b.status === 'confirmed'" variant="ghost" @click="cancelBookingAdmin(b)">Cancel</UiButton>
+                  <UiButton
+                    v-if="b.status === 'calendar_failed' || b.status === 'pending'"
+                    variant="ghost"
+                    :disabled="retryingId === b._id"
+                    @click="retryBookingAdmin(b)"
+                  >{{ retryingId === b._id ? 'Retrying…' : 'Retry now' }}</UiButton>
                 </div>
               </Card>
             </div>