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/ja.json

@@ -2870,6 +2870,5 @@
   "CONFIRMED": "確認済み",
   "PAD / RTLS": "射場 / RTLS",
   "Sea Marks": "航路標識",
-  "Ski Pistes": "スキーゲレンデ",
-  "Open Map Overlays": "オープンマップのオーバーレイ"
+  "Ski Pistes": "スキーゲレンデ"
 }