control centre: status pill top right that opens into a macOS-like panel

Wi-Fi and hotspot (iwd, never D-Bus-activated by a read), VPN (openrc openvpn.*),
Bluetooth (bluez), battery, volume, screen and keyboard light, performance mode
(platform profile + governor + EPP through doas -n), and the external GPU with the
programs using it (drm fdinfo). Icons move to glyph.rs.

src/theme.rs

@@ -73,6 +73,9 @@ pub struct Theme {
 
     // the open media card and the equalizer take the cover's colours as their background
     pub cover_colors: bool,
+
+    // the iwd access point profile the control centre's hotspot starts (/var/lib/iwd/ap/<name>.ap); empty: none
+    pub hotspot: String,
 }
 
 impl Service for Theme {
@@ -80,6 +83,7 @@ impl Service for Theme {
         Self {
             colors: Animation::new(PINK_ON_PURPLE),
             cover_colors: false,
+            hotspot: String::new(),
         }
     }
 
@@ -174,6 +178,7 @@ fn apply(theme: &str, config: &str, startup: bool) {
     let mut theme = Theme::write();
 
     theme.cover_colors = setting("cover_colors") == Some("true");
+    theme.hotspot = setting("hotspot").unwrap_or("").to_string();
 
     // a change in the middle of a fade starts from the colours on screen now
     let now = theme.colors.value();