fix(client): work through the findings from the coverage pass

214 items came out of writing the tests. Real defects are corrected, dead code
is removed rather than covered, and the tests that pinned the old behaviour
move with them.

Also drops two agent coverage scratch files that slipped into the coverage PR
and adds the ignore rule that keeps them out.

client/src/components/Map/MapViewGL.tsx

@@ -7,7 +7,7 @@ import 'maplibre-gl/dist/maplibre-gl.css'
 import { useSettingsStore } from '../../store/settingsStore'
 import { useAuthStore } from '../../store/authStore'
 import { getCached, isLoading, fetchPhoto, onThumbReady, getAllThumbs } from '../../services/photoService'
-import { isCustomPlaceImage } from './placePhoto'
+import { isCustomPlaceImage, photoCacheKey } from './placePhoto'
 import { CATEGORY_ICON_MAP } from '../shared/categoryIcons'
 import { isStandardFamily, supportsCustom3d, wantsTerrain, addCustom3dBuildings, addTerrainAndSky } from './mapboxSetup'
 import { attachLocationMarker, type LocationMarkerHandle } from './locationMarkerMapbox'
@@ -73,6 +73,20 @@ interface RouteSegment {
   drivingText?: string
 }
 
+// Stable identities for the omitted collection props. An inline `= []` / `= {}`
+// default allocates a fresh object on every render, and these props sit in the
+// dependency arrays of the imperative reconcile effects below — so every render,
+// including one caused only by the hover tooltip's state, would tear down and
+// rebuild every marker. That is the "marker recreated under the cursor,
+// mouseleave never fires" case (#1404).
+const NO_PLACES: Place[] = []
+const NO_ROUTE_VIAS: RouteVia[] = []
+const NO_ROUTE_SEGMENTS: RouteSegment[] = []
+const NO_DAY_ORDER: Record<number, number[] | null> = {}
+const NO_RESERVATIONS: Reservation[] = []
+const NO_CONNECTION_IDS: number[] = []
+const NO_POIS: Poi[] = []
+
 interface Props {
   places: Place[]
   dayPlaces?: Place[]
@@ -315,12 +329,12 @@ function createPoiMarkerElement(category: string): HTMLDivElement {
 }
 
 export function MapViewGL({
-  places = [],
-  dayPlaces = [],
+  places = NO_PLACES,
+  dayPlaces = NO_PLACES,
   tripId,
-  routeVias = [],
+  routeVias = NO_ROUTE_VIAS,
   route = null,
-  routeSegments = [],
+  routeSegments = NO_ROUTE_SEGMENTS,
   selectedPlaceId = null,
   hoverDisabled = false,
   onMarkerClick,
@@ -329,17 +343,17 @@ export function MapViewGL({
   center = DEFAULT_MAP_CENTER,
   zoom = DEFAULT_MAP_ZOOM,
   fitKey = 0,
-  dayOrderMap = {},
+  dayOrderMap = NO_DAY_ORDER,
   leftWidth = 0,
   rightWidth = 0,
   hasInspector = false,
   hasDayDetail = false,
-  reservations = [],
-  visibleConnectionIds = [],
+  reservations = NO_RESERVATIONS,
+  visibleConnectionIds = NO_CONNECTION_IDS,
   showTransitRoutes = true,
   showReservationStats = false,
   onReservationClick,
-  pois = [],
+  pois = NO_POIS,
   onPoiClick,
   onViewportChange,
   glProvider = 'mapbox-gl',
@@ -816,12 +830,12 @@ export function MapViewGL({
       if (ev.touches.length !== 1) { cancelLongPress(); return }
       if ((ev.target as HTMLElement).closest('.mapboxgl-marker, .maplibregl-marker')) return
       const t = ev.touches[0]
-      lpStart = { x: t.clientX, y: t.clientY }
+      const start = { x: t.clientX, y: t.clientY }
+      lpStart = start
       lpTimer = window.setTimeout(() => {
         lpTimer = null
-        if (!lpStart) return
         const rect = canvas.getBoundingClientRect()
-        const lngLat = map.unproject([lpStart.x - rect.left, lpStart.y - rect.top])
+        const lngLat = map.unproject([start.x - rect.left, start.y - rect.top])
         lpStart = null
         // Only suppress the tap when OUR fire opened the form — if the native
         // contextmenu beat us to it (dedupe), no click needs swallowing.
@@ -945,7 +959,7 @@ export function MapViewGL({
       // photo for it (that request would 404 for OSM-only places and, worse, the
       // fetched thumb would shadow the user's own image). (#1136)
       if (isCustomPlaceImage(place.image_url)) continue
-      const cacheKey = place.google_place_id || place.osm_id || `${place.lat},${place.lng}`
+      const cacheKey = photoCacheKey(place)
       if (!cacheKey) continue
       const cached = getCached(cacheKey)
       if (cached?.thumbDataUrl) {
@@ -1002,7 +1016,7 @@ export function MapViewGL({
 
       visiblePlaces.forEach(place => {
         const orderNumbers = dayOrderMap[place.id] ?? null
-        const pck = place.google_place_id || place.osm_id || `${place.lat},${place.lng}`
+        const pck = photoCacheKey(place)
         // A custom image wins over the auto-fetched thumb; otherwise fall back to it.
         const photoUrl = isCustomPlaceImage(place.image_url) ? place.image_url! : ((pck && photoUrls[pck]) || place.image_url || null)
         const selected = place.id === selectedPlaceId