Route terminal clipboard through tauri-plugin-clipboard-manager; bump to 0.2.3

navigator.clipboard.readText() triggers WebView2's "Allow clipboard access?"
permission prompt on every paste. The plugin goes through IPC + the OS
clipboard directly, so the prompt never fires.

Wired the Rust plugin, granted clipboard-manager:allow-{read,write}-text in
the capabilities manifest, swapped XtermPane's copy/paste handler to use
the plugin's readText/writeText.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -15,6 +15,7 @@ pub fn run() {
         .try_init();
 
     tauri::Builder::default()
+        .plugin(tauri_plugin_clipboard_manager::init())
         .manage(PtyManager::new())
         .invoke_handler(tauri::generate_handler![
             commands::list_distros,