Widen booking fetch window, resolve governing booking per-night, add turnover icons/nights to dashboard

Backend:
- fetchBookings() window widened from today-only to yesterday..+7 days, so a
  departing booking (arrived any number of nights ago) and upcoming bookings are
  both in view — the previous today-only fetch couldn't see a departing guest's
  arrival date at all.
- New resolveGoverningBooking(): replaces the single-booking-per-site pick with a
  two-tier resolution — (1) any non-cancelled booking whose stay covers today,
  preferring one not yet marked 'departed' (so a departing guest keeps governing
  blue->purple right up until checkout is confirmed, even with a same-day arrival
  also active); (2) otherwise the soonest upcoming booking, purely for colour
  ('booked' ahead of its own prep window). Also computes booking_kind
  (arrival/departure/stayover), current/total night count, and a has_next_booking
  turnover hint (for departure days with another booking already lined up).
- determineRoomState() no longer forces 'vacant' for a future-dated arrival — that
  case is now handled by resolveGoverningBooking() deciding whether a booking is
  relevant to today at all; once picked as governing it always resolves to at
  least 'booked'.
- zone_state table: new booking_kind/current_night/total_nights/has_next_booking
  columns, persisted every poll alongside room_state and exposed via GET /api/status.

Frontend:
- ZoneCard: room name is now followed by a takeoff (departure) / landing (arrival)
  / bed (stayover) icon plus a current/total nights figure, sourced from the new
  status fields. A departure additionally shows a landing icon when has_next_booking,
  hinting at a same-day turnover before the room's actually marked departed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/components/ZoneCard.tsx

@@ -1,9 +1,26 @@
-import { Thermometer, BatteryLow, TriangleAlert, Snowflake, Flame, Fan, Droplet, Lock, Heater } from 'lucide-react'
+import { Thermometer, BatteryLow, TriangleAlert, Snowflake, Flame, Fan, Droplet, Lock, Heater, PlaneTakeoff, PlaneLanding, BedDouble } from 'lucide-react'
 import type { ZoneStatus } from '../types'
 import { ROOM_STATE_LABELS, MHI_FAN_SPEEDS } from '../types'
 
 const AC_DEVICE_TYPES = ['mhi_modbus', 'mhi_mqtt', 'midea', 'daikin', 'home_assistant']
 
+// Departure = takeoff, arrival = landing, stayover = bed (lucide has no "person in
+// bed" icon, so BedDouble is the closest stand-in). A departure also shows a second
+// landing icon when has_next_booking — same-day-turnover hint (someone's due in later).
+function BookingIcons({ zone }: { zone: ZoneStatus }) {
+  if (!zone.booking_kind) return null
+  const iconProps = { size: 13, strokeWidth: 1.75 }
+  return (
+    <span style={{ display: 'inline-flex', alignItems: 'center', gap: 2, marginLeft: 6, fontSize: 11.5, fontWeight: 600, color: 'var(--text-mid)' }}>
+      {zone.booking_kind === 'departure' && <PlaneTakeoff {...iconProps} />}
+      {zone.booking_kind === 'arrival' && <PlaneLanding {...iconProps} />}
+      {zone.booking_kind === 'stayover' && <BedDouble {...iconProps} />}
+      {zone.booking_kind === 'departure' && zone.has_next_booking && <PlaneLanding {...iconProps} />}
+      {zone.total_nights != null && <span>{zone.current_night}/{zone.total_nights}</span>}
+    </span>
+  )
+}
+
 const MODE_ICONS: Record<string, typeof Snowflake> = {
   cool: Snowflake,
   heat: Flame,
@@ -46,6 +63,7 @@ export default function ZoneCard({ zone, onClick }: { zone: ZoneStatus; onClick:
       <div className="zone-card-title">
         <span>
           {zone.name}
+          <BookingIcons zone={zone} />
           {unhealthy > 0 && (
             <TriangleAlert
               size={14}