Replace bare — and generic None in selectors with descriptive None (reason) labels

All optional entity selectors now use the format "None (description)" with
i18n keys instead of hardcoded "—" or bare "None". Added common.none_no_cspt,
common.none_no_input, common.none_own_speed keys to all 3 locales. Updated
frontend context with the convention.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/wled_controller/static/js/features/device-discovery.js

@@ -70,7 +70,7 @@ function _ensureCsptEntitySelect() {
     if (!sel) return;
     const templates = csptCache.data || [];
     // Populate native <select> options
-    sel.innerHTML = `<option value="">—</option>` +
+    sel.innerHTML = `<option value="">${t('common.none_no_cspt')}</option>` +
         templates.map(tp => `<option value="${tp.id}">${tp.name}</option>`).join('');
     if (_csptEntitySelect) _csptEntitySelect.destroy();
     if (templates.length > 0) {
@@ -84,7 +84,7 @@ function _ensureCsptEntitySelect() {
             })),
             placeholder: t('palette.search'),
             allowNone: true,
-            noneLabel: '—',
+            noneLabel: t('common.none_no_cspt'),
         });
     }
 }