Add kiosk desktop app

Tauri app for the Pi. Media runs through the native LiveKit SDK because
WebKitGTK has no WebRTC, with frames encoded in Rust and drawn to a canvas
under the annotation overlay.

apps/kiosk-client/src-tauri/src/main.rs

@@ -0,0 +1,6 @@
+// Prevents additional console window on Windows in release, DO NOT REMOVE!!
+#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
+
+fn main() {
+    pistation_lib::run()
+}