## System details

Omarchy 4.0.0, Hyprland 0.56.2, quickshell-git 0.3.0.r20.g28771c7-2, Qt 6.11.2, icon theme Yaru-blue-dark (yaru-icon-theme 26.04.5.1ubuntu-1), cryptomator 1.19.3-1.

## What's wrong

Symbolic tray icons with a dark fill are drawn at close to the bar background colour, so they are invisible. The tray recolors symbolic icons to the bar foreground, but that recolor does not lighten a dark icon.

Cryptomator publishes `IconName = org.cryptomator.Cryptomator.tray-symbolic`. That SVG is filled `#222222`.

Measured on a dark theme:

- bar background: `#1C2128`
- bar foreground (wifi, battery, clock glyphs): `#E8E6E3`
- rendered Cryptomator icon: `#1D2128`

## Steps to reproduce

1. Run a tray app whose `IconName` ends in `-symbolic` and whose SVG has a dark fill. `cryptomator` with `showTrayIcon` set is one case; its icon is `/usr/share/icons/hicolor/symbolic/apps/org.cryptomator.Cryptomator.tray-symbolic.svg`.
2. Use a dark theme.
3. The tray slot is occupied and clickable, but nothing is visible.

## Cause

`shell/plugins/bar/widgets/Tray.qml`, `TrayIcon` component:

```qml
MultiEffect {
  anchors.fill: trayIconImage
  source: trayIconImage
  visible: trayIconRoot.symbolic
  colorization: 1.0
  colorizationColor: root.foreground
}
```

`MultiEffect.colorization` takes hue and saturation from `colorizationColor` but keeps the source's lightness, so it cannot lighten a dark source.

Source `#222222`, `colorizationColor` `#E8E6E3`, output `#1D2128`. If colorization replaced the colour, the output would be `#E8E6E3`.

The comment on `iconIsSymbolic` says symbolic icons "ship a fixed fill (often near-white)". Many are dark instead: Adwaita's symbolic fill is `#2e3436`, Cryptomator's is `#222222`.

## Fix

Paint the foreground and use the icon as an alpha mask, so the source colour is discarded:

```qml
Rectangle {
  anchors.fill: trayIconImage
  color: root.foreground
  visible: trayIconRoot.symbolic
  layer.enabled: true
  layer.effect: MultiEffect {
    maskEnabled: true
    maskSource: trayIconImage
  }
}
```

Tested locally: the icon renders at `#E8E6E3`, the same as the wifi, battery and clock glyphs, and follows `bar.foreground` when the theme changes.

`brightness: 1.0` before `colorization` also makes the icon visible, but it comes out near-white instead of the bar foreground.