Split Open Map Overlays into Sea Marks and Ski Pistes layers

Each overlay is now its own Infrastructure row instead of a chip on one
shared row: sea-marks (token 6) and ski-pistes (token 7), both
enabled-only, built by createOsmOverlayLayers() from one descriptor
list. Drops the option group and its share-codec defaults, gives each
layer its own name, voice entry and CURRENT-STATE row, and shifts the
token-ledger fixtures to the next free digit 8.

src/i18n/locales/ar.json

@@ -3220,6 +3220,5 @@
   "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",
   "Sea Marks": "علامات بحرية",
-  "Ski Pistes": "مسارات التزلج",
-  "Open Map Overlays": "طبقات خرائط مفتوحة"
+  "Ski Pistes": "مسارات التزلج"
 }