feat(waybar): add custom updates module to waybar configuration

Add a new custom/updates module to the waybar right-side modules that displays available system updates. The module executes fws-updates-check every 30 minutes (1800 seconds) and allows users to install updates by clicking, which launches a kitty terminal running fws-update. Tooltip text is displayed in French.

configs/releng/airootfs/usr/local/share/fws/waybar-config.json

@@ -8,7 +8,14 @@
     "margin-right": 10,
     "modules-left": ["hyprland/workspaces", "hyprland/window"],
     "modules-center": ["clock"],
-    "modules-right": ["custom/keyhelp", "backlight", "pulseaudio", "bluetooth", "network", "cpu", "memory", "battery", "tray"],
+    "modules-right": ["custom/updates", "custom/keyhelp", "backlight", "pulseaudio", "bluetooth", "network", "cpu", "memory", "battery", "tray"],
+
+    "custom/updates": {
+        "exec": "fws-updates-check",
+        "interval": 1800,
+        "tooltip-format": "Mises à jour disponibles — clic pour installer",
+        "on-click": "kitty -e fws-update"
+    },
 
     "hyprland/workspaces": {
         "format": "{id}",