refactor: added notification groups

[ardevd]

No description provided.

[Copilot]

Pull request overview

This PR introduces Android notification channel groups so related notifications (background workers vs timers) are organized together in system notification settings.

Changes:

• Added new string resources for notification group names.
• Created NotificationChannelGroups and assigned existing notification channels to those groups for background workers.
• Created a timers notification group and assigned the active timer notification channel to it.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
app/src/main/res/values/strings.xml	Adds default (en) strings for the new notification groups.
app/src/main/res/values-no/strings.xml	Adds Norwegian string for the background notification group.
app/src/main/java/net/ardevd/tagius/features/background/ZombieCheckWorker.kt	Creates/uses the “background tasks” notification group for zombie alerts.
app/src/main/java/net/ardevd/tagius/features/background/WeeklySummaryWorker.kt	Creates/uses the “background tasks” notification group for weekly summaries.
app/src/main/java/net/ardevd/tagius/features/background/TimerNotificationManager.kt	Creates/uses the “timers” notification group for the active timer channel.

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