refactor: rename aim to upm and extract appimage module

crates/upm-core/tests/install_paths.rs

@@ -0,0 +1,28 @@
+use std::path::Path;
+
+use upm_core::domain::app::InstallScope;
+use upm_core::integration::paths::{desktop_entry_path, managed_appimage_path};
+
+#[test]
+fn user_scope_path_lands_under_home_managed_dir() {
+    let path = managed_appimage_path(Path::new("/home/test"), InstallScope::User, "bat");
+
+    assert_eq!(
+        path,
+        Path::new("/home/test/.local/lib/upm/appimages/bat.AppImage")
+    );
+}
+
+#[test]
+fn system_scope_path_lands_under_opt_upm_dir() {
+    let path = managed_appimage_path(Path::new("/home/test"), InstallScope::System, "bat");
+
+    assert_eq!(path, Path::new("/opt/upm/appimages/bat.AppImage"));
+}
+
+#[test]
+fn system_scope_desktop_entry_uses_upm_prefix() {
+    let path = desktop_entry_path(Path::new("/home/test"), InstallScope::System, "bat");
+
+    assert_eq!(path, Path::new("/usr/share/applications/upm-bat.desktop"));
+}