feat: collapse days hides map markers, Immich test-before-save (#216)

Map markers:
- Collapsing a day in the sidebar hides its places from the map
- Places assigned to multiple days only hide when all days collapsed
- Unplanned places always stay visible

Immich settings:
- New POST /integrations/immich/test endpoint validates credentials
  without saving them
- Save button disabled until test connection passes
- Changing URL or API key resets test status
- i18n: testFirst key for all 12 languages

client/src/pages/TripPlannerPage.tsx

@@ -157,13 +157,36 @@ export default function TripPlannerPage(): React.ReactElement | null {
 
   const [mapCategoryFilter, setMapCategoryFilter] = useState<string>('')
 
+  const [expandedDayIds, setExpandedDayIds] = useState<Set<number> | null>(null)
+
   const mapPlaces = useMemo(() => {
+    // Build set of place IDs assigned to collapsed days
+    const hiddenPlaceIds = new Set<number>()
+    if (expandedDayIds) {
+      for (const [dayId, dayAssignments] of Object.entries(assignments)) {
+        if (!expandedDayIds.has(Number(dayId))) {
+          for (const a of dayAssignments) {
+            if (a.place?.id) hiddenPlaceIds.add(a.place.id)
+          }
+        }
+      }
+      // Don't hide places that are also assigned to an expanded day
+      for (const [dayId, dayAssignments] of Object.entries(assignments)) {
+        if (expandedDayIds.has(Number(dayId))) {
+          for (const a of dayAssignments) {
+            hiddenPlaceIds.delete(a.place?.id)
+          }
+        }
+      }
+    }
+
     return places.filter(p => {
       if (!p.lat || !p.lng) return false
       if (mapCategoryFilter && String(p.category_id) !== String(mapCategoryFilter)) return false
+      if (hiddenPlaceIds.has(p.id)) return false
       return true
     })
-  }, [places, mapCategoryFilter])
+  }, [places, mapCategoryFilter, assignments, expandedDayIds])
 
   const { route, routeSegments, routeInfo, setRoute, setRouteInfo, updateRouteForDay } = useRouteCalculation({ assignments } as any, selectedDayId)
 
@@ -526,6 +549,7 @@ export default function TripPlannerPage(): React.ReactElement | null {
                   onDeletePlace={(placeId) => handleDeletePlace(placeId)}
                   accommodations={tripAccommodations}
                   onNavigateToFiles={() => handleTabChange('dateien')}
+                  onExpandedDaysChange={setExpandedDayIds}
                 />
                 {!leftCollapsed && (
                   <div
@@ -738,7 +762,7 @@ export default function TripPlannerPage(): React.ReactElement | null {
                   </div>
                   <div style={{ flex: 1, overflow: 'auto' }}>
                     {mobileSidebarOpen === 'left'
-                      ? <DayPlanSidebar tripId={tripId} trip={trip} days={days} places={places} categories={categories} assignments={assignments} selectedDayId={selectedDayId} selectedPlaceId={selectedPlaceId} selectedAssignmentId={selectedAssignmentId} onSelectDay={(id) => { handleSelectDay(id); setMobileSidebarOpen(null) }} onPlaceClick={(placeId, assignmentId) => { handlePlaceClick(placeId, assignmentId); setMobileSidebarOpen(null) }} onReorder={handleReorder} onUpdateDayTitle={handleUpdateDayTitle} onAssignToDay={handleAssignToDay} onRouteCalculated={(r) => { if (r) { setRoute(r.coordinates); setRouteInfo({ distance: r.distanceText, duration: r.durationText }) } }} reservations={reservations} onAddReservation={(dayId) => { setEditingReservation(null); tripActions.setSelectedDay(dayId); setShowReservationModal(true); setMobileSidebarOpen(null) }} onDayDetail={(day) => { setShowDayDetail(day); setSelectedPlaceId(null); setSelectedAssignmentId(null); setMobileSidebarOpen(null) }} accommodations={tripAccommodations} onNavigateToFiles={() => { setMobileSidebarOpen(null); handleTabChange('dateien') }} />
+                      ? <DayPlanSidebar tripId={tripId} trip={trip} days={days} places={places} categories={categories} assignments={assignments} selectedDayId={selectedDayId} selectedPlaceId={selectedPlaceId} selectedAssignmentId={selectedAssignmentId} onSelectDay={(id) => { handleSelectDay(id); setMobileSidebarOpen(null) }} onPlaceClick={(placeId, assignmentId) => { handlePlaceClick(placeId, assignmentId); setMobileSidebarOpen(null) }} onReorder={handleReorder} onUpdateDayTitle={handleUpdateDayTitle} onAssignToDay={handleAssignToDay} onRouteCalculated={(r) => { if (r) { setRoute(r.coordinates); setRouteInfo({ distance: r.distanceText, duration: r.durationText }) } }} reservations={reservations} onAddReservation={(dayId) => { setEditingReservation(null); tripActions.setSelectedDay(dayId); setShowReservationModal(true); setMobileSidebarOpen(null) }} onDayDetail={(day) => { setShowDayDetail(day); setSelectedPlaceId(null); setSelectedAssignmentId(null); setMobileSidebarOpen(null) }} accommodations={tripAccommodations} onNavigateToFiles={() => { setMobileSidebarOpen(null); handleTabChange('dateien') }} onExpandedDaysChange={setExpandedDayIds} />
                       : <PlacesSidebar tripId={tripId} places={places} categories={categories} assignments={assignments} selectedDayId={selectedDayId} selectedPlaceId={selectedPlaceId} onPlaceClick={(placeId) => { handlePlaceClick(placeId); setMobileSidebarOpen(null) }} onAddPlace={() => { setEditingPlace(null); setShowPlaceForm(true); setMobileSidebarOpen(null) }} onAssignToDay={handleAssignToDay} onEditPlace={(place) => { setEditingPlace(place); setEditingAssignmentId(null); setShowPlaceForm(true); setMobileSidebarOpen(null) }} onDeletePlace={(placeId) => handleDeletePlace(placeId)} days={days} isMobile onCategoryFilterChange={setMapCategoryFilter} />
                     }
                   </div>