Fix mobile color picker popup clipping and locale update for tabs/sections

Color picker popover now uses fixed positioning on small screens to
escape the header toolbar overflow container. Section titles, sub-tab
labels, and filter placeholders use data-i18n attributes so they update
automatically on language change. Display picker title switches to
"Select a Device" for engine-owned display lists.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/js/features/displays.js

@@ -25,6 +25,12 @@ export function openDisplayPicker(callback, selectedIndex, engineType = null) {
     _pickerEngineType = engineType || null;
     const lightbox = document.getElementById('display-picker-lightbox');
 
+    // Use "Select a Device" title for engines with own display lists (camera, scrcpy, etc.)
+    const titleEl = lightbox.querySelector('.display-picker-title');
+    if (titleEl) {
+        titleEl.textContent = t(_pickerEngineType ? 'displays.picker.title.device' : 'displays.picker.title');
+    }
+
     lightbox.classList.add('active');
 
     requestAnimationFrame(() => {