fix(i18n): Persian brand (فلت‌رندر) + localize aspect 'All Sizes'

- nav/footer/admin brand → فلت‌رندر in fa (FlatRender in en)
- aspect-ratio 'All Sizes' option now uses t('allSizes') (همه اندازه‌ها)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

messages/en.json

@@ -308,7 +308,7 @@
   },
   "auto": {
     "appAdminLayout": {
-      "brand": "FlatRender Admin",
+      "brand": "FlatRender",
       "nodes": "Nodes",
       "renderQueue": "Render Queue",
       "backToDashboard": "← Back to Dashboard",
@@ -765,7 +765,8 @@
       "premiumOnly": "Premium Only",
       "premiumOnlyAriaLabel": "Premium only",
       "sizeAriaLabel": "Template size",
-      "sizePlaceholder": "All Sizes"
+      "sizePlaceholder": "All Sizes",
+      "allSizes": "All Sizes"
     },
     "componentsTrimmerTrimmerVideoPreview": {
       "previewAndCrop": "Preview & crop",