feat: add room-planner app — 3-day HK room view with NewBook integration

NewBook-connected daily housekeeping planner. Replaces the hotelhubmodule-housekeeping-dailylist
WordPress plugin. LXC 120 · 10.10.10.120:3080 · slug: room-planner.

- 3-day booking window (yesterday/today/tomorrow) fetched live from NewBook
- Task completion ticks back to NewBook; room status patches NewBook directly
- 23px border sliver CSS system for adjacent-day booking status
- 3-state filter cycling (off→inclusive→exclusive) for categories and flow types
- Stat filters for outstanding tasks and clean/dirty status
- Rolling 48h activity log with checkout/checkin/status/tasks events
- newbook_pings event bus for future NewBook poller integration
- Room modal with permission-gated guest/rate/notes, task checkboxes, status buttons
- Placeholder sections for future linen-count and routine-tasks modules
- Settings page: task type colours, twin/extra-bed detection, category exclusions
- Mobile-first layout (sidebar desktop, compact top bar mobile)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/lib/booking-flow.js

@@ -0,0 +1,124 @@
+// Shared booking-flow classification logic (server-side).
+// The same logic is duplicated in frontend/src/lib/booking-flow.ts for client use.
+
+export const STATUS_COLORS = {
+  arrived:     '#3b82f6',  // blue
+  confirmed:   '#10b981',  // green
+  unconfirmed: '#f59e0b',  // amber
+  departed:    '#a855f7',  // purple
+  cancelled:   '#94a3b8',  // slate
+  blocked:     '#6b7280',  // grey
+}
+
+// Extract YYYY-MM-DD from a NewBook datetime string
+export function toDateStr(dt) {
+  if (!dt) return null
+  return String(dt).slice(0, 10)
+}
+
+// Extract HH:MM from a NewBook datetime string
+export function toTimeStr(dt) {
+  if (!dt) return null
+  const t = String(dt).slice(11, 16)
+  return t || null
+}
+
+// Find all bookings for a given site on a specific date.
+// A booking occupies a site on viewDate if: arrival <= viewDate < departure
+// (departure date is the check-out day, so the room is vacated on that morning)
+export function bookingsForSiteOnDate(bookings, siteId, viewDate) {
+  return bookings.filter(b => {
+    if (String(b.site_id) !== String(siteId)) return false
+    const arrival = toDateStr(b.booking_arrival)
+    const departure = toDateStr(b.booking_departure)
+    if (!arrival || !departure) return false
+    return arrival <= viewDate && departure > viewDate
+  })
+}
+
+// Find the departing booking for a site on viewDate (departure_date === viewDate)
+export function departingBookingForSite(bookings, siteId, viewDate) {
+  return bookings.find(b =>
+    String(b.site_id) === String(siteId) &&
+    toDateStr(b.booking_departure) === viewDate
+  ) ?? null
+}
+
+// Classify a site's booking state for a given view date.
+// Returns a rich descriptor used to build the room card.
+export function classifyRoom(site, allBookings, viewDate, yesterday, tomorrow) {
+  const siteId = String(site.site_id)
+
+  // Primary: booking that occupies the room on viewDate (arrival <= viewDate < departure)
+  const todayBookings = bookingsForSiteOnDate(allBookings, siteId, viewDate)
+  const departing = departingBookingForSite(allBookings, siteId, viewDate)
+
+  // Adjacent day primary occupants (for border slivers)
+  const prevBookings = bookingsForSiteOnDate(allBookings, siteId, yesterday)
+  const nextBookings = bookingsForSiteOnDate(allBookings, siteId, tomorrow)
+
+  const prevBooking = prevBookings[0] ?? null
+  const nextBooking = nextBookings[0] ?? null
+
+  // Determine flow type
+  let flowType = 'vacant'
+  let primaryBooking = todayBookings[0] ?? null
+
+  if (primaryBooking) {
+    const status = (primaryBooking.booking_status || '').toLowerCase()
+    if (status === 'blocked') {
+      flowType = 'blocked'
+    } else {
+      const arrivalDate = toDateStr(primaryBooking.booking_arrival)
+      const departureDate = toDateStr(primaryBooking.booking_departure)
+      const arrivingToday = arrivalDate === viewDate
+      const departingToday = departureDate === viewDate
+
+      if (arrivingToday && departing && String(departing.booking_id) !== String(primaryBooking.booking_id)) {
+        // A different booking departs same day this one arrives
+        flowType = 'back-to-back'
+      } else if (arrivingToday) {
+        flowType = 'arrive'
+      } else if (departingToday) {
+        // Booking departs today but arrival <= viewDate so they were here — shouldn't normally hit
+        flowType = 'depart'
+      } else {
+        flowType = 'stopover'
+      }
+    }
+  } else if (departing) {
+    // Room had a departing guest but no incoming booking occupies it today
+    primaryBooking = departing
+    flowType = 'depart'
+  }
+
+  const arrivalDate = primaryBooking ? toDateStr(primaryBooking.booking_arrival) : null
+  const departureDate = primaryBooking ? toDateStr(primaryBooking.booking_departure) : null
+
+  return {
+    site_id:          siteId,
+    site_name:        site.site_name,
+    site_status:      site.site_status || 'unknown',
+    category_id:      String(site.site_category_id || ''),
+    category_name:    site.site_category_name || '',
+    category_order:   site.site_category_order ?? 0,
+    site_order:       site.site_order ?? 0,
+
+    flow_type:        flowType,
+    booking:          primaryBooking,
+
+    // Span flags — does this booking continue across the day boundary?
+    spans_previous:   !!primaryBooking && !!arrivalDate && arrivalDate < viewDate,
+    spans_next:       !!primaryBooking && !!departureDate && departureDate > viewDate,
+
+    // Adjacent day context for border slivers
+    previous_booking: prevBooking,
+    next_booking:     nextBooking,
+    previous_status:  prevBooking ? (prevBooking.booking_status || '').toLowerCase() : null,
+    next_status:      nextBooking ? (nextBooking.booking_status || '').toLowerCase() : null,
+
+    // Departure time info for the wider-border badge
+    departing_booking: departing,
+    departing_time:    departing ? toTimeStr(departing.booking_departure) : null,
+  }
+}