Show a basic timeline while the world time is away from live

A bar above the command dock, like a video player's: play and pause on
the left, the world time's date and time in UTC beside it, and Live to
return. It stays hidden while live, so Core looks as before until weather
history is scrubbed or replayed, a host moves the clock, or a link made
away from live is opened. Adds the pause and play_arrow glyphs and the
strings in every catalog.

src/i18n/locales/ar.json

@@ -3218,5 +3218,8 @@
   "Load scenes from an exported JSON file": "تحميل المشاهد من ملف JSON مُصدَّر",
   "Download the timing log of the last play": "تنزيل سجل توقيت آخر تشغيل",
   "Edit anchors, data packs and shot details": "تعديل نقاط الارتكاز وحزم البيانات وتفاصيل اللقطة",
-  "Download this scene as JSON or an asset bundle": "تنزيل هذا المشهد بصيغة JSON أو حزمة موارد"
+  "Download this scene as JSON or an asset bundle": "تنزيل هذا المشهد بصيغة JSON أو حزمة موارد",
+  "World time": "وقت العالم",
+  "Back to live": "العودة إلى البث المباشر",
+  "Live": "مباشر"
 }