fix(hud): state word first, layer names last; CJK cap by locale

Follow-up review fixes:

- The HUD line is STATE | text | LAYERS for the AI summary and the
  fallback line, so the narrow minimal and cyber layouts show both the
  warning and the summary. get_hud_caption builds its caption the same
  way. The unused "{state} {layers}" key is pruned from the catalogs.
- The 20-character cap applies only when the request locale is Japanese
  or Chinese; other languages keep five words around a Han place name.
- enabledLayers names are localized too, and the instructions name layers
  only from enabledLayerLabels, never from feedProvenance or its note.
- The keyless test restores GEV_RATELIMIT_OPENAI_PER_MIN again; comments
  and docs updated.

src/i18n/locales/ja.json

@@ -326,7 +326,6 @@
   "STALE": "更新遅延",
   "PARTIAL": "部分的",
   "FALLBACK": "フォールバック",
-  "{state} {layers}": "{state} {layers}",
   "view band|STREET": "街路",
   "view band|CITY": "市街",
   "view band|METRO": "都市圏",