Live wall review fixes: no not-found flash or map whiplash when the selected incident resolves (#239)

useIncident reports loading until its answer belongs to the current id
(the render before the effect read the previous id's loading=false), and
clears a stale doc on a denied read. LiveView holds the last selected doc
for the same id while the by-id lookup is pending, so a watched incident
resolving no longer deselects (fly to region) and reselects (fly back).

Follow-up for the panel's 'active'/elapsed copy on resolved incidents: #275.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-frontend/components/LiveView.tsx

@@ -284,9 +284,15 @@ export function LiveView() {
     lookupId && lookedUp && lookedUp.incident_id === lookupId && !!orgId && (lookedUp as IncidentDoc).org_id === orgId
       ? lookedUp
       : null;
-  const selected: IncidentDoc | null = activeSelected ?? fetchedSelected;
   const lookupPending = !!lookupId && !fetchedSelected && (lookupLoading || !orgId);
   const notFound = !!lookupId && !fetchedSelected && !lookupPending;
+  // The incident on screen resolving drops it from the active list before its
+  // by-id lookup lands. Hold the last doc for that same id meanwhile, so the
+  // wall doesn't fly back to the region and straight back again.
+  const lastSelected = useRef<IncidentDoc | null>(null);
+  const held = lookupPending && lastSelected.current?.incident_id === link.inc ? lastSelected.current : null;
+  const selected: IncidentDoc | null = activeSelected ?? fetchedSelected ?? held;
+  lastSelected.current = selected;
   const resolvedSelected = fetchedSelected?.status === "resolved" ? fetchedSelected : null;
 
   // The selected incident's own calls, by incident id — no limit, so a long