fix(updater): Sichere In-App Updates mit ureq, SHA256-Integrität und atomarem AppImage-Tausch

Cargo.toml

@@ -29,6 +29,10 @@ egui = "0.27"
 egui-wgpu = "0.27"
 egui-winit = { version = "0.27", default-features = false, features = ["links"] }
 webbrowser = "0.8"
+semver = "1.0"
+sha2 = "0.10"
+ureq = { version = "2.10", default-features = false, features = ["tls", "gzip", "json"] }
+url = "2.5"
 
 [profile.dev]
 opt-level = 1 # Erhöht Rendering-Performance auch im Debug-Modus