Linux-Port: GNOME-Popup + Tray, Terminal-Schriftgröße global

- Popup als rahmenloses Fenster mit D-Bus-Relay (popup.html/ts, Popup.vue);
  GNOME-Extension schiebt es unter den Panel-Button
- Terminal: globale Schriftgröße via settings.json (terminalFontSize),
  Zoom mit Ctrl/Cmd +/-/0 im Terminal
- trayLinux-Icon, Capabilities, App.vue/terminal.html angepasst

src-tauri/capabilities/default.json

@@ -4,11 +4,18 @@
   "description": "enables the default permissions",
   "windows": [
     "main",
+    "popup",
     "term-*"
   ],
   "permissions": [
     "core:default",
     "core:window:allow-start-dragging",
+    "core:window:allow-set-size",
+    "core:window:allow-minimize",
+    "core:window:allow-toggle-maximize",
+    "core:window:allow-close",
+    "core:window:allow-hide",
+    "core:window:allow-start-resize-dragging",
     "autostart:default",
     "dialog:default"
   ]