feat: scaffold Tauri + Svelte client

SvelteKit in SPA mode with Tauri v2. Builds and produces .deb bundle.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/src-tauri/src/lib.rs

@@ -0,0 +1,14 @@
+// Learn more about Tauri commands at https://tauri.app/develop/calling-rust/
+#[tauri::command]
+fn greet(name: &str) -> String {
+    format!("Hello, {}! You've been greeted from Rust!", name)
+}
+
+#[cfg_attr(mobile, tauri::mobile_entry_point)]
+pub fn run() {
+    tauri::Builder::default()
+        .plugin(tauri_plugin_opener::init())
+        .invoke_handler(tauri::generate_handler![greet])
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
+}

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() {
+    client_lib::run()
+}