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_config.js

@@ -1,17 +1,17 @@
 // Configuration tab: frame settings + firmware card + take control.
-// Frame name/mode live in the page header now (frame_header.js) and
-// Calendar settings have their own tab (frame_calendar.js). window.
-// FRAME_API is set by the template. Checkboxes are always sent
-// explicitly as "true"/"false" -- the server treats absent fields as
-// "leave unchanged", so a checkbox must never be simply omitted.
+// Frame name/mode live in the page header now (frame_header.js), Calendar
+// settings have their own tab (frame_calendar.js), and Order/Display mode
+// live on the Photos tab (frame_photos.js) -- photos-specific settings,
+// not device-wide configuration. window.FRAME_API is set by the template.
+// Checkboxes are always sent explicitly as "true"/"false" -- the server
+// treats absent fields as "leave unchanged", so a checkbox must never be
+// simply omitted.
 
 async function saveConfig() {
   const minutes = parseInt(document.getElementById('refresh_interval_minutes').value, 10) || 60;
   const body = new URLSearchParams({
-    order: document.getElementById('order').value,
     orientation: document.getElementById('orientation').value,
     refresh_interval_s: String(minutes * 60),
-    display_mode: document.getElementById('display_mode').value,
     quiet_hours_enabled: String(document.getElementById('quiet_hours_enabled').checked),
     quiet_hours_start: document.getElementById('quiet_hours_start').value || '22:00',
     quiet_hours_end: document.getElementById('quiet_hours_end').value || '07:00',