feat: add 'Show read notifications' setting

[afonsojramos]

Summary

Adds a new notification settings toggle to allow users to control whether read notifications are displayed or hidden in the application. Fixes #708.

Changes

• Added showReadNotifications setting to control notification visibility
• When enabled (default), displays both read and unread notifications
• When disabled, hides read notifications until marked as done
• Includes comprehensive filter logic and UI toggle in settings

Tests

• Added filter tests for the new notification visibility logic
• Added component test for the settings checkbox toggle

[setchy]

I've had this on my half-implemented list for a while, with a few raised and then closed PR attemps...

I think we need to wait until the merged/batched api is finished before merging to avoid rate limits.

Additionally, in the previous PRs I raised for this feature, I had changes to the HoverGroup buttons to hide the "mark as read" option on read NotificationRows

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[setchy]

We should also change the look and feel for read NotificationRows - ie: opacity difference, plus as Read State as a Filter Section option for Read and Unread.

Unfortunately the REST API doesn't indicate a difference between read and done notification types

[setchy]

Unfortunately the REST API doesn't indicate a difference between read and done notification types

To add some further thoughts for discussion, when I last looked into this feature ~2 months or so back that I was 80% convinced to close #708 as not planned since I couldn't see it being that useful alone unless we can find a way to differentiate read + done vs read and undone, or essentially the not done inbox. I timeboxed this but wasn't able to find any attributes within the public REST or GraphQL API endpoints that could help us here...