feat(display): expose list_display_modes and set_display_mode in relay

Svelte callers can now enumerate all display modes and set resolution/
refresh/HiDPI per display through the native bridge.

src/lib/electron/electron_relay.ts

@@ -503,6 +503,30 @@ export async function set_display_layout({
     return await native.set_display_layout({ mode, configStr });
 }
 
+export async function list_display_modes() {
+    if (!native || !native.list_display_modes)
+        return { success: false, error: 'Native handler list_display_modes not available' };
+    return await native.list_display_modes();
+}
+
+export async function set_display_mode({
+    display_index,
+    width,
+    height,
+    refresh_rate,
+    hidpi
+}: {
+    display_index: number;
+    width: number;
+    height: number;
+    refresh_rate?: number;
+    hidpi?: boolean | null;
+}) {
+    if (!native || !native.set_display_mode)
+        return { success: false, error: 'Native handler set_display_mode not available' };
+    return await native.set_display_mode({ display_index, width, height, refresh_rate, hidpi });
+}
+
 export async function power_control({
     action
 }: {