feat(qconnect): add v2_qconnect_get/set_startup_mode commands

String-typed wire shape for predictable serde behavior across the
Tauri invoke boundary. Validates against QconnectStartupMode::from_str.

cc

src-tauri/src/qconnect/commands.rs

@@ -6,7 +6,8 @@
 
 use qconnect_app::{
     evaluate_remote_queue_admission, resolve_handoff_intent, QConnectQueueState,
-    QConnectRendererState, QueueCommandType, RendererReport, RendererReportType,
+    QConnectRendererState, QconnectStartupMode, QueueCommandType, RendererReport,
+    RendererReportType,
 };
 use tauri::{AppHandle, Emitter, Manager, State};
 use uuid::Uuid;
@@ -843,6 +844,19 @@ pub async fn v2_qconnect_set_device_name(
     Ok(())
 }
 
+#[tauri::command]
+pub async fn v2_qconnect_get_startup_mode() -> Result<String, RuntimeError> {
+    Ok(super::startup::load_startup_mode().as_str().to_string())
+}
+
+#[tauri::command]
+pub async fn v2_qconnect_set_startup_mode(mode: String) -> Result<(), RuntimeError> {
+    let parsed = QconnectStartupMode::from_str(&mode)
+        .ok_or_else(|| RuntimeError::Internal(format!("invalid startup mode: {mode}")))?;
+    super::startup::save_startup_mode(parsed);
+    Ok(())
+}
+
 #[tauri::command]
 pub fn v2_get_hostname() -> Result<String, RuntimeError> {
     Ok(resolve_system_hostname())