Enhance CSS test preview with live capture, brightness display, and UX fixes

- Stream live JPEG frames from picture sources into the test preview rectangle
- Add composite layer brightness display via value source streaming
- Fix missing id on css-test-rect-screen element that prevented frame display
- Preload images before swapping to eliminate flicker on frame updates
- Increase preview resolution to 480x360 and add subtle outline
- Prevent auto-focus on name field in modals on touch devices (desktopFocus)
- Fix performance chart padding, color picker clipping, and subtitle offset
- Add calibration-style ticks and source name/LED count to rectangle preview

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

server/src/wled_controller/static/js/features/pattern-templates.js

@@ -18,7 +18,7 @@ import {
 import { API_BASE, getHeaders, fetchWithAuth, escapeHtml } from '../core/api.js';
 import { patternTemplatesCache } from '../core/state.js';
 import { t } from '../core/i18n.js';
-import { showToast, showConfirm } from '../core/ui.js';
+import { showToast, showConfirm, desktopFocus } from '../core/ui.js';
 import { Modal } from '../core/modal.js';
 import { getPictureSourceIcon, ICON_PATTERN_TEMPLATE, ICON_CLONE, ICON_EDIT } from '../core/icons.js';
 import { wrapCard } from '../core/card-colors.js';
@@ -157,7 +157,7 @@ export async function showPatternTemplateEditor(templateId = null, cloneData = n
         patternModal.open();
 
         document.getElementById('pattern-template-error').style.display = 'none';
-        setTimeout(() => document.getElementById('pattern-template-name').focus(), 100);
+        setTimeout(() => desktopFocus(document.getElementById('pattern-template-name')), 100);
     } catch (error) {
         console.error('Failed to open pattern template editor:', error);
         showToast(t('pattern.error.editor_open_failed'), 'error');