Move Order and Display mode to the Photos tab

Both are photos-specific settings (rotation order, how a photo's aspect
ratio gets reconciled with the panel), not device-wide configuration --
they belonged on the Photos tab next to the album/queue settings, not
Configuration. No backend change: both already save through the shared
partial-update /config endpoint regardless of which tab's form sends
them.

server/app/static/frame_photos.js

@@ -1,6 +1,6 @@
-// Photos tab: now-displaying, album picker, and the upcoming grid
-// (rendering/drag logic in queue.js). window.FRAME_API is set by the
-// template.
+// Photos tab: now-displaying, album picker, order/display-mode settings,
+// and the upcoming grid (rendering/drag logic in queue.js). window.
+// FRAME_API is set by the template.
 
 function renderControlBanner(control) {
   const banner = document.getElementById('control-banner');
@@ -74,6 +74,8 @@ async function savePhotoSettings() {
   const body = new URLSearchParams({
     album_id: document.getElementById('album_id').value || '',
     queue_target_len: document.getElementById('queue_target_len').value,
+    order: document.getElementById('order').value,
+    display_mode: document.getElementById('display_mode').value,
   });
   const resp = await fetch(`${window.FRAME_API}/config`, {
     method: 'POST',