fix: skip notification when background tasks are still running

[subtleseeker]

Summary

• Add hasPendingBackgroundTasks callback to SessionNotificationConfig interface
• Check for running background tasks before sending notification
• Wire up the callback in index.ts to use backgroundManager.getRunningTasks()

Problem

Notifications fire when a background agent completes, even if other background agents are still running. This happens because:

1. When a background agent completes, it calls notifyParentSession() which prompts the parent session
2. After the prompt is processed, the parent session becomes idle
3. The session.idle event fires for the parent (main) session
4. Since the parent is the main session, the existing notification filters don't skip it
5. Desktop notification is sent even though other background tasks may still be running

Solution

Add a new optional callback hasPendingBackgroundTasks to the SessionNotificationConfig that is checked before sending a notification. When backgroundManager.getRunningTasks().length > 0, the notification is skipped.

This ensures notifications only fire when the session is truly idle (no background tasks running and waiting for user input).

Testing

Built and tested locally. The fix correctly skips notifications when background tasks are still running.

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Summary by cubic

Prevented session notifications from firing while any background tasks are still running. Notifications now trigger only when the session is truly idle.

• Bug Fixes
  • Added hasPendingBackgroundTasks to SessionNotificationConfig and checked it before sending notifications.
  • Wired the callback to BackgroundManager.getRunningTasks() in index.ts to skip notifications when tasks remain.

^{Written for commit 7b3b9ab. Summary will update on new commits.}

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[cubic-dev-ai]

No issues found across 2 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

[subtleseeker]

I have read the CLA Document and I hereby sign the CLA