allow adding system tray to the island

### Feature Description

title

### Use Case

i use my island like this, if i have to add satellite widget the icons would be unaligned, and looks insanely out of place

### Compositor(s)

Niri

### If Other, please specify

_No response_

### Proposed Solution

add system tray to home compact

### Alternatives/Existing Solutions

allow every widgets to be added to the island

The request concerns the Home Compact island, system tray, satellite widgets, and the Niri compositor, but it names no files or tests. First locate the Home Compact implementation and existing widget or tray entry points; done means adding the tray without misaligning satellite-widget icons, then checking the layout under Niri.

Written by the indexing model from the issue text.