docs(docs): document Brave Origin wallpaper blur and opacity overrides

docs/desktop/umbriel.mdx

@@ -38,7 +38,7 @@ Umbriel watches these files and applies a valid save immediately; `umbriel confi
 | Tablet, touch | mapped to `eDP-1` | niri |
 | Cursor | `Bibata_Ghost` (dark translucent Bibata, AUR `bibata-cursor-translucent`) 28, hidden while typing, follows keyboard focus (so scratchpads open on the output focus moved to). Umbriel exports it as `XCURSOR_THEME` and over XSETTINGS; GTK apps on Wayland read the GNOME settings instead, set once with `gsettings set org.gnome.desktop.interface cursor-theme Bibata_Ghost` and `… cursor-size 28` (dconf, not managed) | Umbriel |
 | Layout | gap 8, presets 0.333 / 0.5 / 0.667, new columns 1/3 (0.8 on the laptop panel, see [Outputs](#outputs)), focus never centers, a lone column centers | niri |
-| Appearance | corner radius 10, no shadows, wallpaper-only blur on every window, tab bar hidden for one tab | niri |
+| Appearance | corner radius 10, no shadows, wallpaper-only blur on every window (radius 10, 4 passes, strong enough to hide wallpaper detail behind Brave Origin's own translucent background), tab bar hidden for one tab | niri |
 | Activation | apps may focus and reveal their windows (`focus_on_activate`), e.g. Noctalia notification actions | niri `honor-xdg-activation-with-invalid-serial` |
 | Overview | zoom 0.4; no hot corner | niri |
 | Animation | springs `0.82,1125` (open), `0.88,2025` (close), `0.85,1463` (move, overview, scratchpad), `0.78,1350` (workspaces) | niri |
@@ -81,6 +81,7 @@ Named scratchpads replace Hyprland's `special:*` workspaces and `omarchy-toggle-
 | --- | --- |
 | every window | blur |
 | `Folo`, `Spotify`, `zen`, `brave-origin`, `gemini-desktop`, `claude-desktop`, `kitty*`, `zed`, `obsidian`, `Beeper`, `chromium`, `com.mitchellh.ghostty` | opacity 0.9, tiled, focused |
+| `brave-origin`, `zen`, `chromium` | opacity 0.97 (overrides the 0.9 above) |
 | `dev.noctalia.Noctalia` | floating 1080 × 920 |
 | `dev.noctalia.UmbrielSharePicker` | floating 800 × 600 |
 | `io.github.lgse.Strata`, `org.gnome.Nautilus`, `com.gabm.satty` | floating, half the output wide, focused |