feat(journey): draw the trips' GPX tracks on the journey map (#1911)

* feat(journey): serve the GPX tracks behind a journey

A journey has no trip of its own, but every entry records the trip it came from,
and a trip's routed geometries live on its places. So the tracks are derivable
without any new storage: GET /journeys/:id/tracks walks that link and returns the
geometries, dropping elevation nothing on the map reads and skipping anything
that is not a usable line.

* feat(journey): draw those tracks on the journey map

Both renderers, Leaflet and GL, plus the mobile map-timeline that shares them.
Solid and in the track's own colour with a white casing, so it reads as a
recorded route rather than as the dashed line that merely connects entries in
time order, and stays legible on satellite tiles.

* feat(journey): load the tracks alongside the journey

Fetched separately from the journey itself: most journeys have no tracks, and a
failed lookup should cost the map its lines rather than the whole page.

* docs(journey): document the GPX tracks on the map

* fix(journey): label tracks with the house map tooltip

bindTooltip's default box ignores the appearance tokens, so it sat there in
Leaflet grey next to markers already using .map-tooltip. Same class now, and an
unnamed track gets no tooltip at all instead of an empty one.

client/src/pages/JourneyDetailPage.tsx

@@ -44,7 +44,7 @@ function JourneyDetailPageDesktop() {
     unlinkTrip, setUnlinkTrip, showSettings, setShowSettings,
     hideSkeletons, setHideSkeletons,
     mapRef, fullMapRef, activeLocationId, handleMarkerClick, handleLocationClick,
-    mapEntries, sidebarMapItems, tripDates, isMobile,
+    mapEntries, sidebarMapItems, tripDates, isMobile, tracks,
     loadJourney, updateEntry, deleteEntry, reorderEntries, uploadPhotos, deletePhoto,
   } = useJourneyDetail()
 
@@ -86,6 +86,7 @@ function JourneyDetailPageDesktop() {
         <MobileMapTimeline
           entries={timelineEntries}
           mapEntries={sidebarMapItems}
+          tracks={tracks}
           dark={document.documentElement.classList.contains('dark')}
           readOnly={!canEditEntries}
           onEntryClick={(entry) => setViewingEntry(entry)}
@@ -441,6 +442,7 @@ function JourneyDetailPageDesktop() {
                   ref={mapRef}
                   checkins={[]}
                   entries={sidebarMapItems as any}
+                  tracks={tracks}
                   height={9999}
                   activeMarkerId={activeEntryId}
                   onMarkerClick={handleMarkerClick}

client/src/pages/journeyDetail/useJourneyDetail.ts

@@ -3,6 +3,8 @@ import { useParams, useNavigate, useSearchParams } from 'react-router'
 import { useJourneyStore } from '../../store/journeyStore'
 import { useTranslation } from '../../i18n'
 import { addListener, removeListener } from '../../api/websocket'
+import { journeyApi } from '../../api/client'
+import type { JourneyTrack } from '@trek/shared'
 import { DAY_COLORS } from '../../components/Journey/dayColors'
 import type { JourneyMapAutoHandle as JourneyMapHandle } from '../../components/Journey/JourneyMapAuto'
 import { useToast } from '../../components/shared/Toast'
@@ -61,6 +63,19 @@ export function useJourneyDetail() {
     if (id) loadJourney(Number(id)).catch(() => {})
   }, [id])
 
+  // GPX tracks of the trips behind this journey (#1260). Loaded separately from the
+  // journey itself: a journey without tracks is the common case, and a failed lookup
+  // should cost the map its lines, not the whole page.
+  const [tracks, setTracks] = useState<JourneyTrack[]>([])
+  useEffect(() => {
+    if (!id) return
+    let cancelled = false
+    journeyApi.listTracks(Number(id))
+      .then(res => { if (!cancelled) setTracks(res.tracks ?? []) })
+      .catch(() => { if (!cancelled) setTracks([]) })
+    return () => { cancelled = true }
+  }, [id])
+
   useEffect(() => {
     if (current?.hide_skeletons !== undefined) setHideSkeletons(current.hide_skeletons)
   }, [current?.hide_skeletons])
@@ -287,7 +302,7 @@ export function useJourneyDetail() {
     unlinkTrip, setUnlinkTrip, showSettings, setShowSettings,
     hideSkeletons, setHideSkeletons,
     mapRef, fullMapRef, activeLocationId, handleMarkerClick, handleLocationClick,
-    mapEntries, sidebarMapItems, tripDates, isMobile,
+    mapEntries, sidebarMapItems, tripDates, isMobile, tracks,
     loadJourney, updateEntry, deleteEntry, reorderEntries, uploadPhotos, deletePhoto,
   }
 }