🌐(frontend) refactor device i18n keys for reusability across contexts

Update localization keys for device toggling and selection to be more
generic, enabling translation sharing between join and room contexts.

Eliminates duplicate translations and creates consistent messaging for
device interactions regardless of application context.

src/frontend/src/locales/nl/rooms.json

@@ -7,12 +7,10 @@
     "home": "Keer terug naar het hoofdscherm",
     "back": "Sluit weer bij de vergadering aan"
   },
-  "join": {
-    "selectDevice": {
-      "loading": "Bezig met laden…",
-      "select": "Selecteer een waarde",
-      "permissionsNeeded": "Toestemming vereist"
-    },
+  "selectDevice": {
+    "loading": "Bezig met laden…",
+    "select": "Selecteer een waarde",
+    "permissionsNeeded": "Toestemming vereist",
     "videoinput": {
       "choose": "Selecteer camera",
       "permissionsNeeded": "Selecteer camera - Toestemming vereist",
@@ -31,7 +29,9 @@
     "audiooutput": {
       "choose": "Selecteer luidspreker",
       "permissionsNeeded": "Selecteer luidspreker - Toestemming vereist"
-    },
+    }
+  },
+  "join": {
     "effects": {
       "description": "Pas effecten toe",
       "title": "Effecten",