Refactor task progress to unified useTaskProgress hook

Replace WebSocket-only useTaskWebSocket with useTaskProgress that
provides a unified task state interface. TaskIndicator no longer
manages its own polling or auth — it receives task state from the
parent via props. Rename wsTasks prop to tasks throughout.

frontend/src/App.tsx

@@ -17,13 +17,16 @@ import { Sheet, SheetContent, SheetTrigger } from './components/ui/sheet';
 import { Button } from './components/ui/button';
 import { Filter } from 'lucide-react';
 import type { GeoJSONFeatureCollection, PropertyProperties, PropertyFeature, POI, POITravelFilter } from '@/types';
-import { refreshListings, fetchTasksForUser, streamListingGeoJSON, fetchUserPOIs, type StreamingProgress } from '@/services';
+import { refreshListings, streamListingGeoJSON, fetchUserPOIs, type StreamingProgress } from '@/services';
 import { poiMetricPropertyName, injectPoiMetricProperty } from '@/utils/poiUtils';
-import { useTaskWebSocket } from '@/hooks/useTaskWebSocket';
+import { useTaskProgress } from '@/hooks/useTaskProgress';
+
+function isTerminalStatus(status: string): boolean {
+  return status === 'SUCCESS' || status === 'FAILURE' || status === 'REVOKED';
+}
 
 function App() {
   const [listingData, setListingData] = useState<GeoJSONFeatureCollection | null>(null);
-  const [taskID, setTaskID] = useState<string | null>(null);
   const [user, setUser] = useState<AuthUser | null>(null);
   const [queryParameters, setQueryParameters] = useState<ParameterValues | null>(null);
   const [submitError, setSubmitError] = useState<string | null>(null);
@@ -44,8 +47,26 @@ function App() {
   const [poiTravelFilters, setPoiTravelFilters] = useState<Record<number, POITravelFilter>>({});
   const [currentMetric, setCurrentMetric] = useState<Metric>(DEFAULT_FILTER_VALUES.metric);
 
-  // WebSocket-based real-time task progress
-  const { tasks: wsTasks, isConnected: wsConnected, subscribe: wsSubscribe } = useTaskWebSocket(user);
+  // Explicit task ID set by fetch-data action (to track as "active")
+  const [explicitTaskId, setExplicitTaskId] = useState<string | null>(null);
+
+  // Unified task progress: WS primary, polling fallback
+  const { tasks, isConnected, subscribe, cancelTask, clearAllTasks } = useTaskProgress(user);
+
+  // Derive activeTaskId: explicit ID if set, else most recent non-terminal task
+  const activeTaskId = useMemo(() => {
+    if (explicitTaskId && tasks[explicitTaskId]) return explicitTaskId;
+    // Fall back to any non-terminal task
+    const nonTerminal = Object.entries(tasks).filter(
+      ([, t]) => !isTerminalStatus(t.status),
+    );
+    if (nonTerminal.length > 0) return nonTerminal[0][0];
+    // Fall back to explicit even if terminal (to show final status)
+    if (explicitTaskId && tasks[explicitTaskId]) return explicitTaskId;
+    // Show most recent task if any
+    const allIds = Object.keys(tasks);
+    return allIds.length > 0 ? allIds[allIds.length - 1] : null;
+  }, [explicitTaskId, tasks]);
 
   // Ref to track accumulated features during streaming
   const accumulatedFeaturesRef = useRef<PropertyFeature[]>([]);
@@ -77,17 +98,6 @@ function App() {
     setUser(passkeyUser);
   };
 
-  useEffect(() => {
-    if (!user) {
-      return;
-    }
-    fetchTasksForUser(user).then((tasks) => {
-      if (tasks && tasks.length > 0) {
-        setTaskID(tasks[0]);
-      }
-    });
-  }, [user, taskID]);
-
   // Load user's POIs
   useEffect(() => {
     if (!user) return;
@@ -235,6 +245,10 @@ function App() {
     }
   }, [queryParameters, loadListings]);
 
+  const handleTaskCancelled = useCallback(() => {
+    setExplicitTaskId(null);
+  }, []);
+
   if (!user) {
     return <LoginModal isOpen={user === null} onPasskeyLogin={handlePasskeyLogin} />;
   }
@@ -248,8 +262,8 @@ function App() {
       setIsLoading(true);
       try {
         const data = await refreshListings(user!, parameters);
-        setTaskID(data.task_id);
-        if (data.task_id) wsSubscribe(data.task_id);
+        setExplicitTaskId(data.task_id);
+        if (data.task_id) subscribe(data.task_id);
       } catch (error) {
         if (error instanceof Error) {
           setSubmitError(error.message);
@@ -347,13 +361,9 @@ function App() {
     );
   };
 
-  const handleTaskCancelled = () => {
-    setTaskID(null);
-  };
-
   const handlePOITaskCreated = (taskId: string) => {
-    setTaskID(taskId);
-    if (taskId) wsSubscribe(taskId);
+    setExplicitTaskId(taskId);
+    if (taskId) subscribe(taskId);
     // Refresh POI list in case new ones were created
     if (user) {
       fetchUserPOIs(user).then(setUserPOIs).catch(() => {});
@@ -379,12 +389,18 @@ function App() {
       {/* Header */}
       <Header
         user={user}
-        taskID={taskID}
-        onTaskCancelled={handleTaskCancelled}
+        tasks={tasks}
+        activeTaskId={activeTaskId}
+        isConnected={isConnected}
+        onCancelTask={cancelTask}
+        onClearAllTasks={async () => {
+          const result = await clearAllTasks();
+          if (result) {
+            handleTaskCancelled();
+          }
+          return result;
+        }}
         onTaskCompleted={handleTaskCompleted}
-        wsTasks={wsTasks}
-        wsConnected={wsConnected}
-        wsSubscribe={wsSubscribe}
       />
 
       {/* Main content area */}