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/components/Header.tsx

@@ -11,28 +11,29 @@ import { TaskIndicator } from './TaskIndicator';
 interface HeaderProps {
     user: AuthUser;
     activeFilterCount?: number;
-    taskID?: string | null;
     isLoading?: boolean;
     onToggleFilters?: () => void;
     showFilterToggle?: boolean;
-    onTaskCancelled?: () => void;
+    // Task progress (unified)
+    tasks: Record<string, TaskState>;
+    activeTaskId: string | null;
+    isConnected: boolean;
+    onCancelTask: (taskId: string) => Promise<boolean>;
+    onClearAllTasks: () => Promise<boolean>;
     onTaskCompleted?: () => void;
-    wsTasks?: Record<string, TaskState>;
-    wsConnected?: boolean;
-    wsSubscribe?: (taskId: string) => void;
 }
 
 export function Header({
     user,
     activeFilterCount = 0,
-    taskID,
     onToggleFilters,
     showFilterToggle = false,
-    onTaskCancelled,
+    tasks,
+    activeTaskId,
+    isConnected,
+    onCancelTask,
+    onClearAllTasks,
     onTaskCompleted,
-    wsTasks,
-    wsConnected,
-    wsSubscribe,
 }: HeaderProps) {
     const handleLogout = async () => {
         if (user.provider === 'passkey') {
@@ -58,11 +59,12 @@ export function Header({
 
             {/* Task Indicator */}
             <TaskIndicator
-                taskID={taskID ?? null}
-                onTaskCancelled={onTaskCancelled}
+                tasks={tasks}
+                activeTaskId={activeTaskId}
+                isConnected={isConnected}
+                onCancelTask={onCancelTask}
+                onClearAllTasks={onClearAllTasks}
                 onTaskCompleted={onTaskCompleted}
-                wsTasks={wsTasks}
-                wsConnected={wsConnected}
             />
 
             {/* Filter Toggle (mobile) */}