deps: i18next 10 -> 23, react-i18next 7 -> 14

Modernizes the whole i18n stack:
- 48 translate([], {wait:true}) / translate() HOCs -> withTranslation()
- react.wait:true -> react.useSuspense:false
- whitelist -> supportedLngs; added compatibilityJSON: 'v3' so our
  natural-language keys + v3 _plural layout keep working (custom
  separators ss/eth/dj preserved)
- backends: xhr -> i18next-http-backend (client), sync-fs ->
  i18next-fs-backend (server); dropped i18next-localstorage-cache
  (was enabled:false); languagedetector 2 -> 8
- ReSendEmail: <Interpolate> (removed in v10) -> <Trans values={{email}}/>,
  dropped the removed bare t export
- saveMissing handler signature (lngs, ns, key, fallbackValue)

Silences the per-component Translate/I18n legacy-context warnings.
Browser-verified es/en switch and <Trans> interpolation on /fires;
REST smoke byte-identical.

package.json

@@ -24,11 +24,10 @@
     "handlebars": "^4.0.11",
     "history": "^4.7.2",
     "html5-device-mockups": "^3.2.0",
-    "i18next": "^10.5.0",
-    "i18next-browser-languagedetector": "^2.1.0",
-    "i18next-localstorage-cache": "^1.1.1",
-    "i18next-sync-fs-backend": "^1.0.0",
-    "i18next-xhr-backend": "^1.5.1",
+    "i18next": "^23.16.8",
+    "i18next-browser-languagedetector": "^8.2.1",
+    "i18next-fs-backend": "^2.6.6",
+    "i18next-http-backend": "^2.7.3",
     "immutability-helper": "^2.5.1",
     "indexof": "0.0.1",
     "iron": "^5.0.4",
@@ -65,7 +64,7 @@
     "react-confirm": "^0.1.16",
     "react-dom": "^18.3.1",
     "react-helmet-async": "^2.0.5",
-    "react-i18next": "^7.4.0",
+    "react-i18next": "^14.1.3",
     "react-leaflet": "^1.8.0",
     "react-leaflet-control": "^1.4.0",
     "react-leaflet-fullscreen": "0.0.6",