Background task completion notifications

[nam-hle]

Summary

Show a balloon notification when a nadle task finishes while the IDE window is not focused or the user is in a different tool window.

Motivation

Users often switch to other work while long tasks run. A notification prevents them from missing the result.

Acceptance Criteria

• Balloon notification on task completion when IDE is not focused
• Shows task name and result (passed/failed)
• Clickable notification opens the run console
• Respects IDE notification settings (user can mute)
• No notification if user is already looking at the run console

Implementation Notes

• Use NotificationGroupManager / Notifications.Bus.notify()
• Register a NotificationGroup in plugin.xml
• Trigger from NadleTaskExecutionListener on process termination
• Check ApplicationManager.getApplication().isActive for focus state