feat(frontend): add task details edit flow

Add a task details action from the entity page and route it to a prefilled edit task page.

Extend the local task API with single-task read and update helpers, and cover the new flow with frontend tests.

frontend/src/router/index.tsx

@@ -8,6 +8,7 @@ const DashboardPage = lazy(() => import('../pages/DashboardPage'))
 const EntitiesPage = lazy(() => import('../pages/EntitiesPage'))
 const EntityDetailPage = lazy(() => import('../pages/EntityDetailPage'))
 const CreateTaskPage = lazy(() => import('../pages/CreateTaskPage'))
+const EditTaskPage = lazy(() => import('../pages/EditTaskPage'))
 const LogsPage = lazy(() => import('../pages/LogsPage'))
 
 function Protected({ children }: { children: ReactNode }) {
@@ -64,6 +65,14 @@ export const router = createBrowserRouter([
       </Protected>
     ),
   },
+  {
+    path: '/entities/:entityId/tasks/:taskId',
+    element: (
+      <Protected>
+        <EditTaskPage />
+      </Protected>
+    ),
+  },
   {
     path: '/logs',
     element: (