Explore places on the map, planner route fixes, and instance-wide Mapbox (#1147)

* feat(maps): add an OSM POI search endpoint (category within a viewport)

New /api/maps/pois queries OpenStreetMap via Overpass for places of a category
(restaurants, cafes, hotels, sights, …) inside a bounding box. OSM-only by design
— it never calls Google, even when a Google key is configured.

* feat(map): explore nearby places on the trip map (OSM category pill)

A floating, icon-only pill over the planner map lets you toggle a POI category and
see those OpenStreetMap places in the current view; clicking a marker opens the
add-place form pre-filled (name, address, website, phone). Single-select with a
'search this area' action after the map moves. Renders on both the Leaflet and
Mapbox maps, and can be turned off in settings (discussion #841).

* fix(planner): anchor timed places when optimising and route transports by location

- The day optimiser no longer reshuffles places that have a set time — they stay
  anchored to their time, like locked places.
- The route now uses a transport's departure/arrival location as a waypoint when it
  has one (e.g. a flight's airport), instead of breaking the route at every booking;
  transports without a location are ignored for routing but still show their leg's
  distance/duration under the booking.

* feat(admin): instance-wide Mapbox defaults in default user settings

Admins can set a shared Mapbox token (plus style, 3D and quality) as instance
defaults, so the whole instance can use Mapbox without each user pasting their own
key. Users without their own value inherit it via the existing admin-defaults
merge; the shared token is stored encrypted (discussion #920).

client/src/components/Map/MapView.tsx

@@ -1,7 +1,7 @@
 import { useEffect, useRef, useState, useMemo, useCallback, createElement, memo } from 'react'
 import DOM from 'react-dom'
 import { renderToStaticMarkup } from 'react-dom/server'
-import { MapContainer, TileLayer, Marker, Polyline, CircleMarker, Circle, useMap } from 'react-leaflet'
+import { MapContainer, TileLayer, Marker, Polyline, CircleMarker, Circle, useMap, Tooltip } from 'react-leaflet'
 import MarkerClusterGroup from 'react-leaflet-cluster'
 import L from 'leaflet'
 import 'leaflet.markercluster/dist/MarkerCluster.css'
@@ -10,6 +10,7 @@ import { mapsApi } from '../../api/client'
 import { getCategoryIcon, CATEGORY_ICON_MAP } from '../shared/categoryIcons'
 import ReservationOverlay from './ReservationOverlay'
 import type { Reservation } from '../../types'
+import { POI_CATEGORY_BY_KEY, type Poi } from './poiCategories'
 
 function categoryIconSvg(iconName: string | null | undefined, size: number): string {
   const IconComponent = (iconName && CATEGORY_ICON_MAP[iconName]) || CATEGORY_ICON_MAP['MapPin']
@@ -118,6 +119,44 @@ function createPlaceIcon(place, orderNumbers, isSelected) {
   return fallbackIcon
 }
 
+// Small coloured pin for an OSM "explore" POI — distinct from the photo-circle
+// markers of planned places; the colour matches its pill category.
+const poiIconCache = new Map<string, L.DivIcon>()
+function createPoiIcon(category: string) {
+  const cached = poiIconCache.get(category)
+  if (cached) return cached
+  const cat = POI_CATEGORY_BY_KEY[category]
+  const color = cat?.color || '#6b7280'
+  const svg = cat ? renderToStaticMarkup(createElement(cat.Icon, { size: 13, color: 'white', strokeWidth: 2.5 })) : ''
+  const icon = L.divIcon({
+    className: '',
+    html: `<div style="width:26px;height:26px;border-radius:50%;background:${color};border:2px solid white;box-shadow:0 1px 5px rgba(0,0,0,0.3);display:flex;align-items:center;justify-content:center;cursor:pointer;">${svg}</div>`,
+    iconSize: [26, 26],
+    iconAnchor: [13, 13],
+    tooltipAnchor: [0, -14],
+  })
+  poiIconCache.set(category, icon)
+  return icon
+}
+
+// Emits the current viewport bbox on pan/zoom so the POI-explore pill can fetch
+// OSM places for the visible area.
+function ViewportController({ onViewportChange }: { onViewportChange?: (b: { south: number; west: number; north: number; east: number }) => void }) {
+  const map = useMap()
+  useEffect(() => {
+    if (!onViewportChange) return
+    const emit = () => {
+      const b = map.getBounds()
+      onViewportChange({ south: b.getSouth(), west: b.getWest(), north: b.getNorth(), east: b.getEast() })
+    }
+    map.whenReady(emit) // ensure the first bbox is captured once the map is laid out
+    map.on('moveend', emit)
+    map.on('zoomend', emit)
+    return () => { map.off('moveend', emit); map.off('zoomend', emit) }
+  }, [map, onViewportChange])
+  return null
+}
+
 interface SelectionControllerProps {
   places: Place[]
   selectedPlaceId: number | null
@@ -367,7 +406,21 @@ export const MapView = memo(function MapView({
   showReservationStats = false,
   visibleConnectionIds = [] as number[],
   onReservationClick,
+  pois = [] as Poi[],
+  onPoiClick,
+  onViewportChange,
 }: any) {
+  const poiMarkers = useMemo(() => (pois as Poi[]).map((poi: Poi) => (
+    <Marker
+      key={`poi-${poi.osm_id}`}
+      position={[poi.lat, poi.lng]}
+      icon={createPoiIcon(poi.category)}
+      zIndexOffset={500}
+      eventHandlers={{ click: () => onPoiClick?.(poi) }}
+    >
+      <Tooltip direction="top" offset={[0, -10]} opacity={1} className="map-tooltip">{poi.name}</Tooltip>
+    </Marker>
+  )), [pois, onPoiClick])
   const visibleReservations = useMemo(() => {
     if (!visibleConnectionIds || visibleConnectionIds.length === 0) return []
     const set = new Set(visibleConnectionIds)
@@ -543,6 +596,7 @@ export const MapView = memo(function MapView({
       <SelectionController places={places} selectedPlaceId={selectedPlaceId} dayPlaces={dayPlaces} paddingOpts={paddingOpts} />
       <MapClickHandler onClick={onMapClick} />
       <MapContextMenuHandler onContextMenu={onMapContextMenu} />
+      <ViewportController onViewportChange={onViewportChange} />
       <LeafletLocationLayer position={userPosition} mode={trackingMode} />
 
       <MarkerClusterGroup
@@ -583,6 +637,8 @@ export const MapView = memo(function MapView({
         showStats={showReservationStats}
         onEndpointClick={onReservationClick}
       />
+
+      {poiMarkers}
     </MapContainer>
     {isMobile && <LocationButton
       mode={trackingMode}