Improve photo cluster interaction on map: open gallery/popover

When using the Immich photo layer on the Dawarich map, nearby photos are grouped into numbered clusters such as 2, 5, etc.

Currently, clicking a photo cluster does not display the photos it contains. The user has to zoom repeatedly until the individual photo markers appear. This is especially inconvenient when several photos have nearly identical GPS coordinates, because they may require a very high zoom level to separate visually.

It would be much more convenient if clicking a photo cluster either:

• opened a small gallery/popover containing all photos in the cluster, or
• automatically zoomed to the minimum level required to separate the photo markers.

A gallery/popover would be preferable, because multiple photos can share almost identical coordinates and may never separate cleanly even at high zoom levels.

This would make the Immich photo layer significantly easier to browse on the map.