fix(background-agent): clear toast tracking when tasks stop

🤖 Generated with assistance of [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/features/background-agent/task-poller.ts

@@ -11,6 +11,7 @@ import {
   MIN_RUNTIME_BEFORE_STALE_MS,
   TASK_TTL_MS,
 } from "./constants"
+import { removeTaskToastTracking } from "./remove-task-toast-tracking"
 
 export function pruneStaleTasksAndNotifications(args: {
   tasks: Map<string, BackgroundTask>
@@ -66,8 +67,17 @@ export async function checkAndInterruptStaleTasks(args: {
   concurrencyManager: ConcurrencyManager
   notifyParentSession: (task: BackgroundTask) => Promise<void>
   sessionStatuses?: SessionStatusMap
+  onTaskInterrupted?: (task: BackgroundTask) => void
 }): Promise<void> {
-  const { tasks, client, config, concurrencyManager, notifyParentSession, sessionStatuses } = args
+  const {
+    tasks,
+    client,
+    config,
+    concurrencyManager,
+    notifyParentSession,
+    sessionStatuses,
+    onTaskInterrupted = (task) => removeTaskToastTracking(task.id),
+  } = args
   const staleTimeoutMs = config?.staleTimeoutMs ?? DEFAULT_STALE_TIMEOUT_MS
   const now = Date.now()
 
@@ -98,6 +108,8 @@ export async function checkAndInterruptStaleTasks(args: {
         task.concurrencyKey = undefined
       }
 
+      onTaskInterrupted(task)
+
       client.session.abort({ path: { id: sessionID } }).catch(() => {})
       log(`[background-agent] Task ${task.id} interrupted: no progress since start`)
 
@@ -127,6 +139,8 @@ export async function checkAndInterruptStaleTasks(args: {
       task.concurrencyKey = undefined
     }
 
+    onTaskInterrupted(task)
+
     client.session.abort({ path: { id: sessionID } }).catch(() => {})
     log(`[background-agent] Task ${task.id} interrupted: stale timeout`)