macos-native: clean branch for cloning and building the Tauri desktop app

Orphan branch with no history — includes the Tauri shell (src-tauri/) and
vendored Three.js (vendor/) that were never pushed before, so a fresh clone
can actually build the native app. Drops the large .pcd sample captures and
editor cruft (.obsidian, .DS_Store); they aren't needed to build or run the
app (point clouds load via drag-and-drop, not bundling).

src-tauri/src/main.rs

@@ -0,0 +1,7 @@
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+fn main() {
+    tauri::Builder::default()
+        .run(tauri::generate_context!())
+        .expect("error while running pcd viewer");
+}