Linux: nativer SNI-Tray für Nicht-GNOME-Desktops, pfadtragende fs-Fehler, Panic-Tracer

- Tray verzweigt: GNOME -> Extension/D-Bus, KDE/Cinnamon/LXQt -> natives
  SNI-Tray-Icon mit Menue (libappindicator liefert keine Klick-Events)
- fs-Aufrufe nennen bei Fehlern den Pfad statt bloss 'os error 2';
  is_dir-Guard in list_pools_in und Usage-Auswertung
- Panic-Hook schreibt kopierbaren Backtrace (profile.release debug = 1)
- AppImage unter GNOME gesperrt (rfd-Dialog), Verweis auf deb/rpm
- deb/rpm liefern die GNOME-Extension mit; Appindicator als Depends
- Bundle-Targets um deb/rpm/appimage erweitert

src-tauri/Cargo.lock

@@ -40,6 +40,7 @@ dependencies = [
  "objc2-app-kit",
  "objc2-foundation",
  "portable-pty",
+ "rfd 0.15.4",
  "serde",
  "serde_json",
  "sha2",
@@ -3118,6 +3119,30 @@ dependencies = [
  "web-sys",
 ]
 
+[[package]]
+name = "rfd"
+version = "0.15.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef2bee61e6cffa4635c72d7d81a84294e28f0930db0ddcb0f66d10244674ebed"
+dependencies = [
+ "block2",
+ "dispatch2",
+ "glib-sys",
+ "gobject-sys",
+ "gtk-sys",
+ "js-sys",
+ "log",
+ "objc2",
+ "objc2-app-kit",
+ "objc2-core-foundation",
+ "objc2-foundation",
+ "raw-window-handle",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "rfd"
 version = "0.16.0"
@@ -3976,7 +4001,7 @@ checksum = "65981abb771e74e571a38196c3baa11c459379164791eba0e67abc1a5fac9884"
 dependencies = [
  "log",
  "raw-window-handle",
- "rfd",
+ "rfd 0.16.0",
  "serde",
  "serde_json",
  "tauri",